I haven't read any posts or comments about the finale yet (I'm over 500 entries behind on my f-list, having been on holiday for a few days - I'll post about that later).
To sum up the finale in one word: OW.
I've just watched it for the second time and the montage at the end was just D:
I did like the contrast between Chase and Cam getting married and walking off holding hands, and Wilson and House in the car together, with Wilson leaving House at the psychiatric hospital.
Also, that's my show. I'm torn between gleefulness that those of us predicting House going into a psychiatric hospital were correct (with all the fic that's likely to provoke) and dismay at poor House looking so broken at the end of the ep.
I'm still not entirely sure which bits of the ep were in House's head, apart from the obvious (with the lipstick etc). At the moment I'm thinking that everything else was real - and I noticed that at one point Wilson said to House that if he was starting to detox (or words to that effect) he should be in more pain (which is when he said that Cuddy wasn't a Vicodin-substitute).
I did like the ddx in what appeared to be a doctors' locker room (and the end bit where we had Foreman's, Thirteen's and Taub's heads all tilted back to look at House in unison), and I liked that the patient's girlfriend came up with the idea that solved the problem. (Is it me, or did he call her Mia when he slapped her and she ran off, and Annie when she came back? It certainly sounds like that to me! :D )
Also, I liked that the donors with the Very Big Check were clearly a gay couple, without it being specifically mentioned. This show does subtle pretty darned well :D