I've had my gaming PC build now for over 2 years, have yet to do a reformat with W7 64. I think it's about time to clean house. Some basic questions...

-Do I need to backup my Steam games? Or will they automatically redownload when I reinstall Steam?
-Should I download the latest drivers and BIOS on a thumb drive before hand?

Now some minor upgrade questions...

-Adding 2 more 4gb sticks for a total of 16gb of RAM, worth it?
-never had a SSD, maybe get a small one for windows and some flight sims? Good brands?
-aftermarket CPU cooler...good one for my system? I have always used stock heatsink and fan, never overclocked anything but would like to try and boost things a bit.

Any other tips that would be helpful? This is mainly a gaming PC so I don't have tons of files that need backing up or anything. Just pretty much games.