Consoles have many advantages, they are a lot smaller than a lumpy Desktop PC, much cheaper, for the performance they give, are and always have been for the gamer who doesn't want to fiddle around having to spend ages looking for parts which will fit together and work (self-build or pre-built route), they have a very large user base, have exclusive games which arn't on PC.
However they do have dissadvantages, can't do things like encode videos etc (like a PC), but they are catching up in that race with emails, internet and browsing etc. They don't have things like Crysis, the ability to upgrade individual parts, smaller HDD storage, and thigns like wireless adaptors are expensive because there're only really official models available.
It all depends on who you are. I'm a soft-core PC gamer with 2 broken PS2 with a brother who wants to buy a PS3, witha load of mates with 360s and some with PCs. At the end of the day, if I wanted something which I could play with a lot of my mates, I'd opt for a 360. But for some reason I went for a PC, because I wanted to experience a self-build, have a better PC gaming machiene and not have to play a 360 on my CRT TV whcih would be the same expeience as on my PS2 or Xbox 1 ....