Re: @Sutekh: GFWL
Actually, it depends what you play. If you're part of the MW3 crowd, yeah, you'll struggle.
But almost all Valve titless can and probably will be ported (given that Valve/Steam are basically the same company). Hell, it'd be worth trying it on Linux just to play HL2:Ep3 a few days early if they really wanted to push that side of Steam.
And then you have the myriad indie titles, thousands of them, that are offered singly, through humble bundles, etc., almost all of whom already support Linux versions (e.g. Altitude, Dungeons of Dredmor, Gish, etc.). Hell, there's DOSBox-based games galore on there from the classic titles.
Sure, maybe not everything will come over, but you won't be staring at an empty game list. At least, not much worse than an XP users (and I've never bought a game that *demanded* DX10 because it just reeks of bad programming to me, given that it does little of value that isn't achievable on DX9).
Even ignoring that, quite a lot is "Wine-able" software even on the AAA list. You see bugs filed against Wine for games within seconds of them being released.
Linux drivers? The biggest impetus to AMD/nVidia to pull their fingers out might be a multi-million dollar games store running their client on Linux desktops, for example.
It's an obstacle, but no more an obstacle than, say, trying to get a GfWL game working from a bare-bones install (I just had that fun on Windows 7). And any progress is progress. Personally, I think I'd download Steam on a Linux machine just to finally revel in the thing I've been asking for for nearly a decade now and could never understand why they don't didn't it.