I have a 3CD Atlantic box set called Birth of Soul that is outstanding and I thoroughly recommend it . Also Genius of Modern music on Atlantic is great as is Modern Sounds in Country and western music .
For Muddy Waters I have lots of those old Charly Blues masterworks CDs that used to sell for 5 or six quid and all the Muddy Waters are great. The original Chess recordings are best. I particularly recommend Real Folk Blues Vols 1 and 2.
If you are in a Blues buying frame of mind I'd also recommend the incomparable Howling Wolf,Sonny Boy Williamson, Lightning Hopkins, Little Walter. Looking thorugh my CDs they are all released by Rhino(Atlantic) who must own the rights to Chess the great Chicago label.
Rays Jazz and Blues on Shaftesury Ave has a great Blues section downstairs.
John
Bring me my Nightshirt