What I like about the PS3 is that I can sit comfortably on my sofa in front of my 32" Samsung LCD HD TV (not 1080p but 1080i unfortunately).
On the downside I tend to prefer using a keyboard and mouse to play first person shooters. I know Skyrim isn't classed as one but I played Oblivion mostly in first person and when in combat it will probably be better using a keyboard and mouse than a controller.
Also, there is the issue of graphics and overall performance. Does the PS3 degrade over time performance wise? I haven't a clue how my PS3 will compare to my iMac performance wise but here is the spec of my iMac if it helps:
Windows 7 (32 bit)
ATI Radeon HD 4850 512MB
500GB HD
3.06 Ghz Intel Core 2 Duo
4 GB RAM
Thanks in advance and if this should be moved elsewhere I apologise.