Last year my mom passed down a Lamy Safari that was completely destroyed and after trying and failing to get it to work, I resigned myself to my good ol' cheap gel pens. But this post pretty much re-ignited my interest. Right now my Amazon cart has a universal cartridge, a Jinhao x750 in black night sky, zebra g nibs, and Diamine ink. So thanks for that :p

Speaking as someone who's recently done the same thing with calligraphy, I'm happy to help you do so. Except for the hit to your pocketbook, of course. ;-) I've heard decent things about Jinhao. Apparently they are very good for their price, but being a "cheap chinese knockoff", are more susceptible to defective units. Make sure you order from a reputable seller who will allow you to return it if it fails, but hopefully it won't. A nice thing about some Jinhao pens is that the nibs are replaceable with many #6 nibs, so you have some options there.

I decided to go for the diamine because it was cheap and only 30ml, so if this is something that I actually really like (I print pretty small, my 0.4mm gel pens have become my holy grail, so I can be pretty picky about this stuff) I'll spring for the Iroshizuku and Noodler inks I've fallen in love with.

I've heard excellent things about Diamine ink. I ordered some Diamine Oxblood because I wanted something that looked like dried blood, and Diamine Majestic Blue because OH MY GOD look at those colors. Yes, that's just one ink being used: it goes from blue to red as you apply more ink. That's some magic ink, there. (This is called "sheening".) I'll be ordering some Noodler's Black Swan in Australian Roses (again with the glorious names!), J. Herbin Emerald of Chivor 1670 Anniversary Ink and Rohrer & Klingner Alt-Goldgrun (Old Golden Green) because they perform similarly. The Noodler's ink is definitely the most cost-effective, but you can order a sample kit of sheening inks from Goulet if you aren't sure which you want.

I've also been lusting over water brush pens... anything you can tell me about those?

I'm afraid I don't know much about the brush pens as yet. I've used some micron brush pens before, but never one supporting fountain pen inks. That said, I plan to get back into it. There is an artist named Kevin Eslinger that does some utterly amazing work with Dr. Ph. Martin's Bombay India Ink. He basically paints like you would with watercolor paint, and then blows on the fresh ink through a straw, making those cool blown/dripped patterns you see. I bought some of the ink and some traditional brushes, but I'm also looking into some brush fountain pens as well. Noodler's and Platinum both have some that I've been eyeing.