yep - agree the skiing is fab but it's also superb in summer
we had a place in Chamonix for over 10 years before we sold up (too many Brits spoiling the town frankly - it lost it's Frenchness) so know the valley extremely well.
things to do - absolutely tons but the must do's are
cablecar to the Aiguille du Midi - 3800m - and fantastic views of Mt Blanc and surrounds and of the whole area. go on a clear day natch and take warm clothes as even on a hot summer day it will be cold up there.
take the Montenvers cog railway to the Mer de Glace - a glacier that comes all the way down from the top of Mt Blanc. has an ice cave to visit in summer and is just a great viewpoint.
cablecar to the top of Brevent - views across the whole Mt Blanc massif
as for runs/walks/hikes - the valley has something like 500km of marked trails from valley level to high altitude. you can run all of them if you want but most people stick to the valley ones for that. Chamonix hosts an annual marathon (very tough with lots of climbing)and the world famous Ultratrail du Mont Mlanc (UTMB) which is an 122km trail race around the mountain taking in high passes in France, Italy and Switzerland. not for the faint of heart and tough to get into (you need ultra experience)
you can hire mountain bikes, do climbing courses (all French mountain guides are trained in the town), go glacier walking, paragliding, horse riding. so much and so many things to do.
great bars and restaurants from basic to swish. a must visit is the Brasserie du Mt Blanc - a pub that brews it's own beer - we know it well! bookshops aplenty with guides and maps to cover everything you can think of.
and for gear junkies - sports shops with as much technical kit that you would never use in a lifetime. make sure you have a good credit card limit!!
I could go on but it's easier to point you at the
Chamonix website for info.
one note of warning - avoid the place in late July and August as it's absolutely heaving with holidaymakers as over 100000 people descend on the place. it's mayhem. be warned. June and September are fab
if you want any specific info - PM me.