Steam has
Borderlands and it's DLC on sale. $10.19 for the game, and $3.39 each for the expansions.
Also on sale at Steam:
Foreign Legion: Buckets of Blood $2.49
DogFighter $8.49
Week Three of GamersGate Summer Sale has started. I don't have time for a complete list right now, but it's a lot of strategy games. Civ IV, Spellforce, Company of Heroes, Europa Universalis and a lot more.
GamersGate has a lot of crap on sale this week....But also some very, very good titles. I won't list them all, just the ones that struck my fancy :-P
Spellforce Universe
All versions of Spellforce and Spellforce 2 are on sale, but if you're going to get any of them (and they're very good games), get the Universe bundle for €10. It's both the original and the sequel, both with expansions. That's roughly 150 hours of SP playing time.
Sword of the Stars Complete Collection
Supposedly THE best 4X space game out there. I haven't played it yet, but the base game, plus all expansions, for €20? Won't find it cheaper any time soon.
THQ Complete Collection
I personally dislike THQ for the way they've handled some of their products (most notably Titan Quest, which the developers weren't allow to issue a patch for), but these packs are quite worth it. Mind that this pack is cheaper, but isn't as complete, as its Steam counterpart.
Stronghold Collection
All four of the Stronghold games for €7.50. Castle building economic/warfare sim. Very good at what it does, though they're a but love-it-or-hate-it.
Grand Ages: Rome
€5 for what boils down to Caesar V. Nice city building/strategy thingie set in Roman times. A bit of a shame they don't have the bundle with the expansion for €7.50 or something, but oh well.
Civ IV Complete Edition
Doesn't need an introduction, does it? Anyway, €10 for the game with both expansions is still a steal.
Europa Universalis III Complete Edition
€7 for the game and both expansions. A less visually attractive, less combat focussed, version of Total War. Or something. Anyway, very nice mark-off of an absolute classic.