[water-data-dude]

The thing that I really like about fountain pens is that you can get a WAY finer line with one than you can with other pens. My favorite is the Pilot Kaküno, which is actually pretty damn cheap (in the ballpark of $15) but if you get the version with the extra fine nib it gives you (surprise surprise) a really fine line. I personally like it more than the more expensive pens I tried out, but I also never waded all that deep into the expensive end of the product pool. Spending more than $50 on a pen would shrivel my soul to ashes.

I can’t find it on Pilot’s website (hope they haven’t discontinued it), but it’s available on Amazon, etc.

Obligatory caveat: pen enjoyability is pretty subjective. I put a lot of value on stuff like how it feels when I’m writing and a fine line (so I can write tiny in margins, and just because it looks cool IMO), but your mileage may vary substantially.