Ian, would you recommend the 35mm or the 50mm? Both are the 1.8 and I need a good low light lens.
I have both lenses, and if you asked my suggestion I'd say, well, BOTH!
But in all seriousness, it really comes down to which focal length you would find most useful. Set your zoom to 35, and then set it to 50 and observe the different lengths, etc. Whichever one fits, I'd go with that lens. I'm very happy with both lenses, both are great bargains.
Image quality wise I'm hard-pressed to determine which is sharper, and I doubt many people could tell the difference. The AF-S on the 35mm is nice, and I like the focal length a bit better as it is the "normal" length lens on the crop sensors. The 50mm, however, makes a nice complement too it as I can get a little bit more reach for portraits. At around $100 brand new you really can't complain either! I would still say that's the best photography-related $100 I've ever spent was on my 50.