i would get a burner that burned + and -. there is another thread labeled "buying a dvd burner (Sony...)" it might help u decide.
The Pioneer DVR106 is most certainly the best to buy and does do +/-R/RW. It is only £132.99 from Bigpockets.co.uk. There is a DVR107 coming out in december that does +/- and writes at 8x 0 DVD in 7mins or so. Chris