Hmm. There are certain things I like and don't like, but they generally revolve around fluff rather than crunch.

I don't like alternate timelines for fluff that I like, for example. As much as I adore the SWSE game, someone I know invited me into an alternate timeline game where the rebellion lost and the empire continued to rule the galaxy. I just was not interested.

On the other hand, I will NEVER play 4e Forgotten Realms because I loved the setting prior to their massive changes. I loved the multitude of plot hooks, the thousands of detailed locations and iconic characters and places and deities. In fact, 4e crunch requires such massive changes to any existing 3.x D&D campaign fluff that I won't play it at all in any setting I'm familiar with. I'm not going to try 4e until the Eberron sourcebook is out, I think...I've never tried eberron and want to, but have no attachments to the existing 3.5 Eberron because I've never played it.

I think part of why I'm rather accepting of various types of crunch is that I appreciate different aspects of them. My first RPG experience was with using a Palladium based system, and I thought it was great fun, because I'd never played anything else. Palladium is AWFUL.

West End Games Star Wars d6 was my next experience, and I loved it. Still like it, but it lacks some detail and finesse. I've also got mixed feelings on the difference between class/level based systems and more free-development systems. They both have their advantages. My three favorite games (d20 3.5, Exalted 2e, and SW Saga) are all so vastly different there's no real factor in common I can point at to say "I need this."