ok, so what film should be used and more importantly, developing, where?
Depends what you want! Fine grain B&W then XP2 (Ilford); for coarser grain (but still not too obtrusive) FP4 (Ilford) and for coarser grain, HP5 (Ilford) or Tri-X (Kodak). If you're after golfball grain, push either of the faster films (HP5 and TriX) to 1600 or beyond!
For colour prints, take your pick! Personally, I stick with Kodak or Fuji and tend to stay up in the 400 ISO area (since the film development to reduce grain for APS use, 400 ISO grain is almost as fine as 100 was back in the '80s)
For slides, Fuji's Velvia gives saturated colours (some might say oversaturated) with the Sensia range being a little more realistic.
D&P is a minefield though. I prefer to pay a bit extra and get mine done on the High St. That way, if there's a problem, I can go into the shop and get the problem sorted while with postal services, you can never speak to the person you need to! I use the lab prints as proofs- if there are any pics that deserve enlarging, I scan them, process them and print them at home.
B&W D&P used to get done at home but now would go to a local processor - XP2 can be dealt with by any C41 equipped lab (although some are ignorant and can't accept that a B&W film can be put through their soup...) while the others I mentionned need proper B&W chemistry - I'm sure there are London based people here who could tell you where to go. Ilford do mail order D&P - look at their website for info and an addy.
Slides get sent off to FujiLabs. Not the cheapest but consistently good results. They tend to all get scanned when they get back and the good 'uns printed.
The F90 is a great camera - I bought one as back up body to an F4, but the AF system was so much quicker that most of the time the F4 got relegated to back up.