Strop shoppe
Tabac
Both super easy to get great amounts of great lather.
Mikes is great but a little trickier to lather. Strop shoppe does take a while to ship their soaps. I've read of resellers who are faster. Another great, easy soap is speick. Only available as a stick, but if you don't like it as a stick (I don't) you can cut it up or grate it into a container or bowl or ramiken.
+1 on each of these suggestions, almost no point in repeating what's been said but I think these are the 3 best. IMO Strop Shoppe is my favorite but Mike's and Tabac are right there as well. All produce high quality lather and smell awesome.