[quote name='shadylane']should i sell them based on the systems? i have them ranging in all platforms[/QUOTE]
Sell them individually to maximize $$, bundle the less valuable games (i.e. sports) into lots to unload them. Sell here or on craigslist, Gamestop will give you absolutely next to nothing for your games.
If you're committed to trading in to Gamestop, wait for a trade in X number of games, get X% extra credit, or the trade 2 get an extra $10 as mentioned above.