I'll second the Crawler recommendation. They are, as the name might suggest, voiced with muscular blues in mind; they've got a distinct bump in the mids (compared to a classical PAF-type spread, as you'd find in the Mules or the hotter Abraxas), and are not over-burdened with highs. :) And, as noted, they're very versatile pups in general.
That said, if you want something not as hot, I'd think the Mules or maybe even better the Stormy Mondays oughta be great for classic blues tones. (Not so much bump in the mids there, though, as the slightly hotter-than-PAF BDs, I would think.)