US-05 is oriented towards primarily American beers - APA, Amber Ale, Cream Ale, dry Stout, hell I've used it for Porter and had great results. Gives a very clean ale taste, not a lot of "riff raff" contributed by way of estery flavors.
S-04 is oriented towards British styles - it makes a killer Bitter/ESB, Porter, Stout, English Pale, Hobgoblin, etc etc etc. The S-04 is fruitier tasting. But it's really good.
There's a wheat strain out there that I've not tried yet. There's also one that's rumored to be Belgian-ish. But not. But sorta. I still don't get the deal on that one. But overall, I love Fermentis (Safale) yeasts, and at $1.50-$2.00/pack, I keep 2 of each on hand in case of a stuck ferment or dead yeast or etc.
Nottingham is great stuff too!