I play with a GTV1, made by Genesis Trading for Paintball inc. Stock, it cost about $100. It's a very simple, sturdy blow-back design,with a verticle powerfeed, which can easily be upgraded. It takes most Spyder parts. I'd recommend a new barrel, expansion chamber or in-line regulator, pressure balanced valve, venturi bolt, eletronic trigger frame and a 12 volt Revolution. Add a 20 oz CO2 tank or a cheap air system, and you are ready to rock!
http://www.gt-2000.com/
http://www.pbreview.com/1141/1/0/
Or you could probably pick up an second hand Autococker or a Black Dragun for about the same money.
The very best thing to do is not to take my word or anyone else's opinion about any gun. Go out and try them for yourself. The best one for you is the one you feel most comfortable with.
Have fun and play safe