There's also 49th Parallels EPIC espresso which is a pretty light bean, lighter than Black cat. Both are really good in their own ways though.
I think most specialty espresso blends like the one's most people recommend here are lighter espresso roasts. Over roasting destroys the delicate flavours I believe.

Starbucks roasts their espresso blend (and probably allot of the other blends) way too dark, and you end up with a really ashy charcoal type taste, which might taste ok with lots of unhealthy syrups added to it and lots of milk, but not so good on its own or with just milk as a cappuccino.
I was surprised at first how different coffee beans can taste so different from each other (if not burnt to hell)
I tried a coffee bean from Kenya at an espresso bar and it (a shot of espresso) actually tasted pineapple-y. (Which I really didn't like, but it was pretty cool).

I used to enjoy Kicking Horse Cliffhanger espresso but the last bag I got was similar to starbucks, really dark, ashy tasting. So that's another one to avoid if looking for lighter blends.