I miss writing with fountain pens, and use gel rollerballs exclusively now (cheap, waterproof, I don't cry if I lose it, and the office has boxes of them). I like them well enough, and my writing is more legible ... but I really miss the experience of writing w/ a fountain pen. The feel is very different.

If you're curious, one of the cheaper ($3-$4) disposable fountain pens (I think it was Pilot?) were a great introduction. When I first used one (on nice paper that didn't suck up all the ink into ugliness), it was amazing, even though I know there are better ones out there.