I was in exactly the same boat, really wanted the latest technology, and wasn't sure I could stand the niggle knowing that I didn't have a full resolution etc..
I've just bought a 40W3000 and a PS3 and i can only say i'm really pleased with the SD picture as i thought it was going to be really ropey. I wanted a nice stand as well, so i got the RHT-G800, so it made sense to go Sony all the way as it all hooks together very nicely, both in terms of looks, and technology (Bravia Theatre Sync etc)
With some setting changes it really does look pretty good, and thats on a really old Sky box and a really old Scart lead.
I was blown away by the quality of the PS3. It took me back to the first time i bought a new pc, with an amazing (at the time) gfx card and played Half-life. You get the same amazing crispness of graphics and motion, except on a huge 40inch TV!
Not tried Blu-ray as yet, need to buy myself a few dvd's...
Excellent set in my opinion, extremely pleased.