IIRC, Cracker got a fair amount of mainstream exposure in the early 90s. Granted, they've fallen off of the mainstream radar, but for a time they were well thought of.
"I will not be pushed, filed, stamped, indexed, briefed, de-briefed, or numbered!"
I'm not disputing that Cracker is a good (great? perhaps) band, only that I don't think they could qualify as being really all that underrated.
I always thought that, outside of "How Soon is Now," The Smiths never quite got the recognition they deserved, though they do enjoy quite a nice cult status. And, for putting out the best album of the past half decaded, the Magnetic Fields are virtually unknown.