Manufacturer is generally more important then the style. Generally all airsoft aeg's work the same so how it looks like outside is up to you. Though the advice in the Airsoft Newbie Buying Guide about styles is good. Generally ak47, m16/m4 or mp5 are good starter gun styles due to the availability of accessories and upgrades.
Bargain basement is Aftermath stuff. Both the Broxa (full stock MP5) and the Kraken (AK47) are decent bargain basement guns. Stay away from Aftermath's Kirenex or Knight (both M4 variants) and the Lycaon (collapsible stock MP5) though, not a good rep.
If you're willing to go up alittle more you could get a JG. Yeah JG's are China clones but they're getting quite respectable nowadays. Go up alittle more and you could get one of the G&G M4's. G&G is the cheapest of the midgrade guns. Next would be an ICS which is a higher end midgrade gun. The first of the highgrade guns is G&P, there's some debate on whether this is the lowest of the higrade guns or if it should rank higher. Either way they make nice guns.
If you can afford it, highgrade guns such as Tokyo Marui or Classic Army are the way to go.
I did extensive research and settled on the Tactical Carbine version of the Classic Army M15A4 (basically a full stock m4) as my first gun. If an Armalite is what you're looking for then I think it's the best of all possible versions. You have the shortened M4 carbine barrel, which makes you less likely to smack your barrel off something when turning quickly, combined with the full stock which houses a large battery. Small batteries don't have near the run time of a large battery, not to mention that the reinforced slip ring (the ring that keeps the fore-grip on) is really stong. While this is mostly a good thing and a big step up over CA's previous M15 versions, it makes changing small batteries in the field very difficult if not impossible.
CA's M15A4 series in general is a big step up over their previous versions and as far as stock armalites go they're probably the best. All metal where the real steel version is, the plastic parts where the real steal version is plastic are made of high quality enhanced nylon fiber rather then abs for great texture and feel. Classic Army has a deal with Armalite so you get all the proper markings. Plus that deal also goes to show the quality of the manufacture, Armalite wouldn't put their name on a shoddy product.
Internally the gearbox is reinforced metal and all the gears are metal as well. It fires hotter stock then Tokyo Marui's as well, firing at 300-320 fps where your average TM only fires 280-300 fps.
All in all this is a great starter gun if you can afford it. Because it's all metal you don't have to worry nearly as much about breaking it and you won't get any of the wobble or creaking that is infamous in stock TM M4/M16's. Unfortunately affording it is the biggest problem, they're not cheap. Though they'll be considerably cheaper for you then for us.
As you can probably tell, I'm a big fan of Classic Army. One thing to keep in mind about Classic Army is they now have two lines, a proline and a sportline. Originally they were easy to tell apart because the proline had the metal body and the sportline had a plastic body but recently CA has been releasing their sportlines with metal bodies. The price tag should still allow you to easily tell the difference, the sportline being considerably cheaper then the proline but it's still something to keep in mind. All the pros that I went over above were regarding the proline model. The sportline model has cheaper everything internally and externally.
There's alot of people that will expound the virtues of G&P as well. And I'll admit the externals of G&P are very nice, easily on par with CA, in some cases better. The reason why I don't say G&P over CA though is much the same reason why people weren't big fans of CA up until a few years ago: their quality control for the internals is not the greatest. That means a fair number of lemons. CA got a handle on this a few years ago and they've been making great strides in terms of their rep ever since, but G&P isn't quite there yet. This is simply my personal opinion and there are many people that would likely disagree with me, but it's something to keep in mind. ICS is about a cheap a gun as you can go and still get full metal out of the box, I haven't read alot about this manufacturer but needless to say it's not in the same league as CA or G&P. It's what someone on a budget but determined to get full metal would aim for. TM, due to Japanese law, are almost all abs plastic and fire alittle cooler then many guns but their internal reliablity is incredible. They will literally last for decades if left stock.
One of the perks of going with an M16/M4 variant is that mags are dead easy to come by and dirt cheap. You can get Star brand mags for like $5 a mag or less, plastic yeah but sturdy none the less (Star is also the only brand that makes realcaps too). Metal mags will run you a fair bit more, $15 to $30 a mag. There's no real reason to go with metal over plastic for mags except looks/realism. Though of course if you're going to go hicap then you might as well get metal ones. As to Brands, TM and CA make good mags. I've heard pretty good stuff about MAG brand mags as well. King Arms not so much, especially for M4/M16 mags. Star is always a good affordable fallback too.
Some people say you need to shell out for batteries, mags, camo, chargers and ammo in the begining. Most of that isn't necessary right off the hop. The stock battery will do you for awhile. Most of the guns come with a hicap (high capacity (300-600 rounds)) mag that will also do for awhile. I do agree that a good charger would be a sound initial investment, but not a total requirement, especially if you plan to get a good battery down the road and don't care if the cheap wall charger fries your stock battery. Camo isn't really required in the beginning either, just some dark clothes. Ammo, yeah obviously a requirement but even good ammo (BB Bastard) only costs $10 for two thousand rounds.
So truely, all you really need to start is the gun, a bag or two of ammo and good eye protection (which will run you between $30 and $50). That said, if you can afford it then it all helps. Camo would cost about $100, a chest rig or vest would cost another $100. A good loadout of mags, even the cheap Star mags, are going to cost at least $50. A good charger is at least another $50, with another $50 for a good battery. A sidearm is another thing that people like to have but isn't really necessary.
Sidearms aren't really required right away so if you're on a limited budget then hold off on the sidearm for now. If you have the budget for it then what you want in a sidearm depends on two factors (besides cost of course) whether or not full metal is a must and exactly what model you're partial to. Certain manufacturers tend to make certain models better then others. If full metal is a must then the best choice that isn't going to cost you an arm and a leg is probably KJW, especially for the M9 which they do very well. You'll see alot of WE's around, they're cheap and full metal but tend to have problems, especially their 1911 models. KJW has a rep of having mag problems, but I have two KJW pistols and I haven't had any trouble with my mags. If full metal isn't a must then WA or TM would be very good choices.
My Classic Army M15A4 Tactical Carbine without external addons:
My baby, CA M15A4 Tactical Carbine with m203 grenade launcher, red dot sight and taclight: