So, despite having to play in 15-minute long segments because of regular crashes with the most stable combination of fglrx and wine versions (which I'm blaming mostly on ATI's fglrx drivers, since nVidia owners seem to be able to play Source games stably, for the most part), I've completed
Portal.
As anyone who has read the professional reviews will know, Portal is, as well as being an interesting puzzle game, also hilarious. I actually found that GLaDOS becomes less amusing once you escape your planned death - her passive aggressive threats lack, for the most part, the core humour of the earlier voice-overs with their surrealistic evocation of the collision between Mad Science and Public Safety Warnings. By comparison, the turrets, with their ironically cheery personalities, oozed a certain pathos for me (I was glad that the worst I could do to them was knock them over, as I felt somewhat protective of the delusional little things) and were easily better than late game GLaDOS.
Of course, the end credits song redeemed GLaDOS totally of her late-game weakness, helped along by the perkiness of the Curiosity Core; that said, it needed a second listen before I was sure that it was the work of genius that reviewers claimed (apparently, it grows on you). I find myself hoping for a GLaDOS cameo in Half-Life 2: Episode 3...
The puzzle section of the game (what would be considered the meat, if it weren't for the putative dressing being so excellent) is, perhaps, slightly too easy - without spoilers, I didn't have any real trouble solving any of the puzzles, other than in the execution (my reactions are perhaps not quite as fast as they could be, and there were places where you seemed to need more pixel-perfect positioning than perhaps was reasonable) - but, then, this might be considered more of a proof-of-concept, and so we can give it some leeway in this.
Interestingly, the Developer's Commentary suggests that they had to lower the difficulty curve after playtesting, which makes me keen to try out the bonus levels at some point. (And, indeed, the fan contributed levels, which include new features like Weighted Storage Spheres...)
I'm also getting through George R R Martin's A Song of Ice and Fire sequence - more comments on this, and on GRRM in general, in a week or so (after I've finished A Storm of Swords.)