Guitarists with a well developed "voice" - looking for suggestions

I find myself gravitating to melodic prog-rock, especially groups that have a guitarists that plays his instrument like a vocalist. Obvious examples would be Pink Floyd and Camel - I think Gilmour and Latimer are great representations of what I like. There are other really great guitarists that I can appreciate, like Bjorn Riis, but for me they are missing that guitar "voice" that I love so much. I'm trying to key into the factor that makes the guitar work transcend, but the best I can come up with is the "voice" concept.

Other guitarists that really work for me include Marillion's Rothery and Mark Knopfler. The common factors seem to be that they're all relatively "slow hand" players (speaking of which, Clapton's another good example, although he's missing something else that I can't put my finger on...maybe his crazy bleeds through?), and they seem to focus more on the tone and perfect note vs quick, technical riffs. Players like Jeff Beck and Van Halen the elder (jury's still out on his son, who is impressive in his own right) just don't do it for me, although I can see that they are obviously masters in their field.

Any other recommendations? It doesn't necessarily have to be prog rock, although that's where my tastes lean.