I'm a fountain pen user/collector too - though I have more than a few ballpoints, rollers and pencils too.
I won't go on at length here, but I would say that fountain pens are wonderful and since "rediscovering" them about five years ago, they are a daily use item for me. I only use ballpoints if the situation absolutely demands it...
Anyone who has not tried a Parker 51 and loves to write, should track one down. They are still plentiful on eBay. On the less expensive side, a Parker 45 is a wonderful, inexpensive fountain pen and it also takes cartridges (unlike the 51).
Other great makes include Sheaffer, Waterman, Aurora, Esterbrook, Pelikan...
IMO the best rollerball out there is the Lamy 62/63 series which goes in a number of their pens, including the Accent line. It's a wide, satisfying rollerball that never clumps and is smooth to the last drop. Not cheap, but good.
There are a lot of good cheap office pens out there today - the G2 series and almost anything Pilot is generally good.
Enjoy!