Wow, thank you all for valuable information =)

I'm not really planning to change from HC-110 very soon (although I do have a pack of XTol in my cupboard where food used to be ).

It's interesting to get a glimpse of what the differences really are, because, coming into this pretty late in the game, there are a whole heap of chemical alternatives and usually the answers and papers can cause even more confusion.

I'll surely take a mental note of the chart Neal linked to, looks like HC-110 is in the middle of the pack.
- The big plus (for me) with HC-110 is that it's a long lasting developer, because I shoot very small volumes and I find it easy to use and also gives very nice results.
My untrained eyes, would probably have hard time differing between the same film developed in XTol and in D-76, I'm just not that seasoned yet. (plus, my metering is usually a bit iffy as well, so there are several sources for error over here ^^)