I finally finished Halo 3, I enjoyed playing it, but after spending weeks avoiding spoilers I was disappointed in the ending. I know, Halo doesn't sport boss fights... unless of course you count the scarab battles which are great, but ending in a -SPOILER- car race against gravity, somewhat anticlimactic. I do look forward to some 4 player legendary coop, with of course known friends as randomly hooking up ends up in the predictable hell of 13 year old racist homophobes. I truly would rather play with my ten year old son, he is good, funny, and not a total tool.
It's hard to overstate my satisfaction with Portal. It is by far the single most striking game I have played with my kids. Both my kids (10+9) can sing the song on command. All I have to do is fire up the "this is a triumph" refrain and they both bust into synchronized song.
I haven't decided what's next for me, although I probably should finally buy Bioshock, I am somewhat torn on PC vs 360 on this title. I thought that the HLep2 was a no brainer on the PC particularly as the mod scene is so important when it comes to replay value... I don't know if this is as important in Bioshock. The main issue with purchasing a game on the pc for me, is that I don't like sharing my pc, it's easier to share the 360 and watch someone play but on the pc I feel stymied by sharing with the kids.
On the other hand I should really commit to Dead Rising, a marvel of a game that is as hard to finish as riding a bike into a lake, but somehow much more enjoyable.