Cree xm-l's are currently the hot mass production led...although our resident guru, Trout, may correct me on this.
TBH a few of our group have gone for the first one you link to, although their P7 ones bought last year are still working perfectly - just a few fancied a spare and at that price would be rude not to. Just stick the battery in a plastic bag before putting it into the pouch.
One of the P7 18650 torches works perfectly with an Exposure helmet mount - I'll dig out the sku tomorrow and let you know which one, charger, adaptor and batteries.
If you wanted an xm-l bar mounted light relatively quickly, then resident battery guru Smudge could sort you out - higher price but I sense the speed of delivery and after-sales will be excellent - he's a good bloke:
http://www.mtbbatteries.co.uk/