Ok, I haven't been on TSR for about 2 years now but feel I have to contribute here.
I'm an English student at Churchill (yup, not a scientist) and I, and indeed all other students there that I know of absolutely love the place.
I really don't know where to start in trying to express how great it is.
As for the architecture, believe me, the beauty of Trinity etc. is less astonishing by about week 3. Comparatively ALL Churchill rooms are large and the inter-connecting design of the quads means that all are really light and airy, and at the same time you are really close to all of your friends.
Mates of mine in Trinty and Peterhouse say that they would rather be in Churchill purely for the fact that, to take Trinity as an example, their 1st years live alone and have little communication with the other year groups. As Churchill is technically the largest Cambridge college all students live on site so mixing between the year groups happens naturally. I can't stress what a great community Churchill has.
As for distance, it's another plus. I have a bike but haven't used it for at least 2 terms. It's a 10 min walk to town and a 5-10 min walk to the Sidgwick site. It is another plus because when you just want to get out of college and have a breather, town is a great place to have a stroll around. If you live in town you have pretty much nowhere to escape to.
As for the arts/science thing, it's not that noticable. The science emphasis is an important part of the college but arts students are just as vocal and present as the scientists. Plus, because there are less of us, we get alot of attention and funding directed at the relative few. Academically, the college is really happy at the moment as we're (don't quote me on this) something like 2nd in Law and English and 1st in History. I'm not quite sure of which ranking I'm mentioning but the college did get all congratulatory about it.
Anyway, this is becoming a novel. Check out Churchill, it's amazing.