Almost any. See here for a very comprehensive review (I've extracted a couple of comments):-
http://www.dcresource.com/reviews/fuji/finepix _s7000-review/
The S7000 can also use NEARLY ANY third-party external flash. More on that later.
At the center of the picture is the S7000's hot shoe. The camera can sync with an external flash as fast as 1/1000 sec. You will probably need to manually set the settings on the flash. Fuji recommends using "A" and "M" mode on the camera when using one, as well.
The S7000's pop-up flash means no redeye. There's a bit of what I'd call flash reflection, but no red. (Great!)
Now for THE site for digital cameras (albeit biased to the USA):-
http://www.steves-digicams.com/2003_reviews/s7 000.html