Being a Hild Beder I'll try to answer a few of your questions:
Hild Bede is probably slightly less traditional in some ways than Hatfield. Both colleges still wear gowns to matriculation. Hatfield have regular formals where (I think, someone kick me if I'm wrong) they still wear gowns, Hild Bede have about two formals a term (which I feel makes them a bit more of a special occasion) which are black tie but don't require gowns.
The distance Hild Bede is from town si vastly exaggerated by most people, it's about 7 minutes walk at the most. I think the distance factor is only a real hassle if your lectures are on the science site (which English lectures shouldn't be). Obviously Hatfield is the closer of the two but it's not a big thing.
There are plusses and minuses to Hild Bede's layout, it is true that some accomodation (like Ravensworth, where I was in first year) is barely even in the college grounds, but Hild Bede also has the advantage of a big site with lots of grass to sit on in summer and nice gardens. Also, some Hatfield accomodation isn't in the college proper so I don't think there's much of a difference between the two in this respect.
I prefer Hild Bede (I'm trying not to be biased here) - basically I'm not a big fan of the Bailey college cramptness, I think it's nice having a bit of scenery and stuff at your college, rather than having to be in Durham city centre pretty much all the time. There's also the stigma that Hatfield is the rah college (even though it is a fact that Hild Bede has the largest % of independent school entrants), that might also get annoying. HB isn't the college I'd apply to were I applying now (that "honour" goes to Collingwood), but I would apply there over Hatfield.
I've already mentioned the public school thing - Hatfield is perceived to be public school, but Hild Bede is as much or even more so. Hild Bede is supposedly the most sporty college (mainly because we have the most people to choose from!), but Hatfield's pretty into its sports too so there's not much difference.
"Aesthetically pleasing females" really depends on the intake each year - that said, it probably levels itself out so not much between them.
Hope that helped a bit, I tried to objective.