Matterhorn, Lion route
Aguille du Midi, anything
Mont Blanc, tourista route, but midweek.
Petit Dru
Ditto Dru on the Walker Spur
If you've got time to head to Cassis, get to Les Calanques and trip out on some of the stuff that Gaston Rebuffat put up way back when. I soloed a bunch of it about 4 years ago on our engagement trip. I've got a guidebook, but you have to be able to read Freedom (my then-fiance'/now-wife can, so the guidebook worked for me).
Ride the cable car from Punta Hillbrunner (Italian side) to Chamonix. Bring a "friend" for the "Halfway to Heaven Tango" We did!