Interesting comments about the Hilton - I might try that next time - I always assumed that being at T4 it was not practical for T1/2/3. Chance to get the bonus 1000 virgin miles makes this sound appealing although for value for money, Hilton are very poor compared to the Marriott and Starwood chains in my experience.
I stay at heathrow hotels a lot when flying out - the park and fly deals mean that its not much more than the parking itself and its so much easier and relaxed to stay close by rather than a long stressful drive the morning of a flight - leaving 2 hours of buffer for the M25 in my case!!
I've stayed at Marriott, Renaissance, Sheraton Skyline, Sheraton Heathrow and Raddison. All on Bath Road. I don't mind the Hoppas although they can be a bit unreliable in terms of amount of time to wait. I'm not often in a rush though, so never found them too bad.
Of the above hotels, the best value is Sheraton Heathrow - they do park and fly for 109 for 15 days. The thing I really like though is the fact that they do 7 quid per day for parking on site if you stay a night. This is brilliant if only away for a few days. I think this is as cheap as any of the major long stay car parks. Also, online booking has rooms for 55 quid per night for weekends.
mcjock