If I like St. Germain I'll like......

I think you might like Tortoise, especially TNT. Cinematic Orchestra as well. Moby and Gnarls Barkley as well have a similar vibe if maybe in a little more of a pop sense. I've always shied from the most popular stuff and mined deep for the more obscure but recently have been listening to some of these albums from Gnarls Barkley, Moby and Gorrillaz and they are really good and fun to listen to on the hifi.

The great Marc Moulin, sadly deceased in 2008.

You can click through his discography (including the 2009 3cd tribute box) here:

http://www.marcmoulin.com/disco.html

Malcolm McLaren "Paris" is a sure shot.

I second Bizango1's recommendation of Down to the Bone-Manhattan to Staten. I would also try Praful-One Day Deep, Four 80 East-en Route, Down to the Bone-The Urban Grooves and Crazy Vibes and Things.

I second the Cinematic Orchestra. Good stuff for what it is!