They're all the same. They all put most games in the store at least 50% off, and rotate popular titles and indie hits through at 75% off. Although I do like the fact that the summer sale is 2 weeks long.
OP, you got some great games, and it's good to see that you watched GMG's site. Their deals recently have been significantly better than Steam's, and the majority of their games are in fact Steam keys. Grats.
Unfortunatelly i have so little time and so many great games, that i have already 3 years covered in gaming:
Stracraft II when friends are online,
Tribes Ascend whenever i want to relax,
Baldurs Gate Trilogy when its raining outside,
Starcraft Broodwar when i want to get hyped,
F.E.A.R 1+expansions/Amnesia the dark descent when i want to get scared ( FOr example while in bed ).
Oblivion and skyrim when ill have like 400 hours to burn,
And random games i want to finish:
Just Cause with 100% destruction,
Make my own campaign in crysis 1 with the mods out there to make it look better,
Finish Mass effect 1 2 3 with full renegade femshep,
And im quite sure im forgeting about 50% more...
I think, with about 3 weekends free time (and this is pre-girlfriend) each month, i got enought games to play till 2014 .