topdealman:
Why not blu ray?
Maybe it wasn't shot in HD.
There aren't too many TV shows which pre-date HDTV yet have been released on HD-DVD or Blu-ray (the only ones which spring to mind are the original 1960s seasons of Star Trek).
Friends was certainly broadcast well before HDTV took off, so Blu-rays will only be available if it was shot on film and Warner think it's worth remastering from scratch.
It also might be a bit pointless if widescreen versions of the masters aren't available.
Shame though!
EDIT:
BTW; this in-store deal is NOT "cheaper than online". It's a penny more (apart from you'd get 5% Quidco online and your discs sometime next year - assuming the CWU hasn't caused the complete bankruptcy of the Royal Mail).