Until about 2 weeks ago I hadn't been behind a kit since 1993. Suffice to say I hadn't kept up with the products that have been developed since then. I test drove a variety of electronic (interesting, but I didn't care for the sounds) and acoustic kits and settled on a Mapex M birch 6 piece fusion size kit.

Cymbals are next. I have a pretty good handle on what Zildjian A, K and Z's are and sound like. They don't appear to have changed much. I was hoping someone could very briefly outline the different lines offered by Paiste and Sabian. I need to understand what's top shelf, whats beginner etc. I'm hoping to build a a collection from used, top shelf stuff but I don't know what is top shelf from those two makers and what isn't. Since ebay is a likely source I need a little education to have any hope of getting some decent stuff.

If you like Zildjians, you may just want to stick with them.  There's always an abundance of Zildjian A's on eBay for a decent price, and they'll work pretty well for most music.

As for other companies, Sabian and Zildjian are the easiest to compare.

Zildjian A ~ Sabian AA / AA El Sabor
Zildjian A Custom ~ Sabian AAX
Zildjian K ~ Sabian HH
Zildjian K Custom ~ Sabian HHX / HHX Evolution
Zildjian Z Custom ~ Sabian AA Metal-X

Sabian also has two newer lines, Paragon which were made with Neil Peart, and Vault, which don't really have a direct comparison to any Zildjian line I know of.

Paiste and Meinl have a little bit different sound from Sabian and Zildjian, so you'd probably want to try some of those out firsthand before you get into them.  The main problem with telling you what Paiste's top end is that they retire cymbal lines, so their current top end is Traditionals (K like), Signatures (A Custom type sound), 2002, Dark Energy, and their new Twenty line.  I don't know too much about Meinl's, haven't really had a chance to play any of them in a store.  For the most part, Paiste uses a different bronze mixture than the others, that's why it's a little hard to make a direct comparison, you just have to let your ears test them out.  I like Paiste's sound better, but it would be easier for you to find a set of A Zildjians for cheaper on eBay, and still have a professional sound.