First gun, you say? A... uh... copy of a copy of a copy of the TM M9 Springer. I think it most closely resembled a UHC, but in clear. Probably has made its way over time into a few land fills by now - but I'm not too sure what is still around and what ended up in pieces following multiple, intentional collisions with solid cement walls and floors, lol.
First GBB (and non-clearsoft, if you may) came shortly thereafter - a early generation Socom Gear Wilson Combat CQB Elite (POS if you like to tinker - finding aftermarket parts & internals that are confirmed fits is a real pain). This one is gone now.
First LPAEG was... oh let's not even go there. Still have it somewhere in a closet, I think. At least it wasn't shitsoft and it gave me a few cheapo rail accessories, and rails too - though I've yet to actually mount them to my G3-SG1.
First AEG was an Aftermath Lycaon. Gearbox cracked on me in my first 20 min on a field, and I gave up on researching what exactly I needed to do to fix it almost immediately. Held onto it for a while (dumb move), before selling it off as a parts gun to a local guy who'll be building a loaner MP5 for new players.
First gaming gun was thus a Cansoft KWA KP45. I love them, it works great as a secondary, though it isn't quite as accurate as the TM-type hop up system. Goes much better on gas with a metal slide and much less cool down than any other GBB I've messed around with (minus KSC Glocks, those are pretty awesome).