I've a fair few friends who say that the modern Doctors are a lot easier on the eye than Classic. Personally, I think it's just the relative youth, just about every actor who has played the Doctor on screen looked pretty damn fine in their early days - I'd argue most of them looked good as they acted the Doctor too, but assuming they didn't for a moment...
Peter Davison (youngest to play the Doctor, at twenty-nine, prior to Matt Smith stealing the crown)
(on the right)
Colin Baker (I'll give you, he's not the most typically good looking, but are any of them, really? Don't say Tennant, he's skinny, Scottish and has mad staring eyes. Face it.)
(scary 70s porno tache)
Sylvester McCoy (not easiest guy to find photos of, but I actually think he's alright looking these days too... I mean, look at Eccleston)
I personally don't think, other than who had the best hairdos* as the Doc, there's much to choose between...
(* Pertwee, Smith, Tennant.)
Also, film/extra Doctors (in some cases young, in Lumley and Broadbent's case, too awesome to bother with younger pics):
Jim Broadbent (played the Doctor for 2 spoofs, one with Victoria Wood the other as REG's regenerated self)
Joanna Lumley (wins, hands down, title of best looking Doctor, old or young)