If I can make a suggestion: Get Garry's mod. It's basically a sandbox, do whatever you want kinda thing. Plus, if you get Counter Strike: Source, you can play a game on it called Trouble In Terrorist Town. I swear, that is the most addicting game I've played in a while.
No not at all, plenty of games i am sure I will find throughout, I don't really know the PC collection though however. Only things I can think of I will be playing the day I finish building my PC though is SimCity 2013 and Minecraft. The rest will come throughout the days.
Tekkit is a mod that adds tech mods, it adds electricity to minecraft and all kinds of stuff to create whatever you want like nuclear stations etc. Its like a bagillion mods in one.