I hate doing stuff on the PS3 which I could do 100x quicker with a keyboard and mouse. I'd probably be looking more towards using the computer for most stuff and ideally the TV for youtube and Skype video connections only to utilise the big screen? I guess it depends on how you setup your life/gear etc.
I think you'd want to purchase the BD remote or add the $100 harmony PS3 adaptor, unless you're happy controlling the DVD etc now from a hand controller etc.
I personally find the PS3 works best in tandem with a computer to house the music/video media files etc. You can't do folders on the PS3 itself and you can't (I think?!) bring play lists across from a computer, so I find it hard to find songs etc from a giant list of them etc. - Though truthfully I probably just need to spend the time to clean up the metadata on the files to include correct album/artist info etc.