Seems odd to be discussing this here at all, but I will add my thoughts.
I'm a PC guy but I do have a 360 that I got mostly for the Kinect and to play occasional fighting games (Mortal Kombat etc) that aren't available on PC. I end up not gaming on it much but it is tremendously useful as a complement to the TV/home theatre setup. I end up using it to watch HD Netflix content, Hulu (sometimes), Zune (yes Zune is nice for on demand movie serivice) and there are other options there that I have not even looked at yet like Vudu and some other channels. With the Kinect you can control things strictly through hand gestures and voice which is quite slick and an underrated feature. I still use a universal remote for it sometimes, I dont like navigating TV channels with the game controller. Maybe I'll play games on it one day if I find time.. hehe..
As far as PS3, all the TV-content related stuff is much better integrated on the 360. Most of the hardcore console gamers I know seem to agree that the games play better on 360. Sony touted the power of the PS3 but apparently its tricky to take advantage of, so if you pay attention to popular titles like Skyrim and Battlefield 3 and such, you always hear of problems with frame rate etc. on PS3, bugs that never seem to get fixed. I think Sony oversold the public on what the hardware could do... it looked attractive a few years ago because Bluray players were expensive, but now they've come way down, so I think the 360 TV integration is more important.
Then there is the notorious Sony network breach. Sony doesn't understand security, Microsoft leads the industry in security. Yes, 12 years ago or so MS was getting spanked regularly when it comes to security, but now they are on top. Check out recently pwn2own results, Internet Explorer held up much better than Chrome/Firefox etc.
Anyway, if you want to play games at their best, you need a good gaming PC with a nice video card. This is especially true if you play first person shooters... the console experience is really lame compared to that on a PC where you are aiming with the mouse. The difference is kind of like composing music on a computer keyboard versus a MIDI controller. The MIDI controller is much more natural and musical. Not only that but games look better and play better on a good PC, and generally cheaper... you can find crazy deals on Steam where you buy the PC versions for a fraction of what the console discs cost. Downside of course is PC hardware costs more and while you don't need to be a techie, its not quite as brain dead as consoles because you occasionally need to update drivers, be aware of your hardware specs, etc. You can get a 360 controller for your PC to play racing games and things that play better with a gamepad, but to my knowledge you can't just plug a mouse into a console and get the same benefit.
On the other hand invest in a good gaming PC and you can also use it for music assuming you use your computer for music production. Things like fast CPU and lots of memory help with music making, softsynths and fx just as they do with games. In the case of nVidia video cards, there are even plugins that take advantage of CUDA (a feature of nVidia cards) that will run them on your GPU instead of your CPU.