I like Alembic CX (Compression wounds strings) as they have a very balanced piano-like tone, but they don't seem to hold their peak tone very long. Of course, they are better in that regard than Rotosounds, which I swear go dead if I just look at them! DR Hi Beams are my current choice,as they seem to hold their peak tone for several weeks, and they are similar in tone to the Alembics. DR's Marcus Miller Fat Beams are a little less bright, with a slighty boomier low end than the Hi Beams.
By the way, I buy my strings through juststrings.com They carry strings by many makers, including Alembic, DR, Elixir, GHS, Dean Markley, D'Addario, TI, etc at good prices.