The NEC VR5 would also be a good contender if you want HD in the future.
Personally, by the time HD becomes widespread we may have other flat panel technologies available, I am going to enjoy my PWD7 for a few years yet.
there are no plasmas with 1024x768 res and less than £1500, 2 that will possibly accept HD signals and down scale are the LG PX11 (under £1500 huge owners thread on here) and NEC VR5 (smaller following thread on here)
buying anything without a demo is likely to lead to dissapointment.....Why do you want HD ready if you only have £1500 to spend, this seriously limits your options, Hitachi, and panasonic are very popular but dont accpet 720p @ 50Hz
Due to the way the screens process the video data for display, all flat-panel technologies have the potential to go out of sync with an external audio system (amp/receiver), and Sky is susceptible to lip-sync issues on some of the lower bandwidth channels already. It's something that can be addressed with either a dedicated "audio delay" box or a suitably-equipped amplifier (like the Yamaha 650/750 for example). I wouldn't worry about it too much.
My feeling is that if you can only afford £1500 for a plasma then you are unlikely to be able to afford HD-DVD, Blu-ray or skHD for some time to come. It'll be a while before the players cost less than your display, and skyHD will have a hefty premium just to have the box, then half the HD content will be PPV
If you're bogging yourself down about HD, then you should end up concentrating on quality ie something with the res. No true HD res panel at the moment in your range but some that can handle downscaled options.