I'd definitely get a Hope Hoop on a 355 rim, excellent value, light, easy to convert to tubeless.
And cheaper than the £101 quoted above if bought online from many of the major web based bicylce retailers!
717 is a bit narrow, and a bit flimsy for most uses. Fine for pure XC riding, but even then, you can get lighter and wider rims these days. Stans 355 (or it's new replacement the Crest) gets my vote, though if you want to go wider, there's always Mavic's own 719 (a good rim) or the Stans Flow you could choose without too much weight penalty. Rims like the Mavic 321 provide too much of a weight penalty IMO unless most of your riding is gravity based.