I just got back into brewing and of the last 7 beers I've made, I used 7 different strains (although one was a lager). I like to try out different strains to see how the flavor is affected and how the yeast behaves. Of course, there are many variables like pitching rates and temperatures that will have a an influence, so it looks like I've got a lot of experimenting to do
I say go crazy with using alternate strains for a "beer style". Beer styles were born by using what brewers had available in their environment at that time. You are where you are at this time in brewing history, so knock yourself out - be your own brewdog!
I think breweries stick to one or two strains so they can manage the yeast easier. This, unfortunately results in similar tasting beers. I recently toured Boulder Beer and they only use WYeast 1056 and all their beers taste alike, IMHO.
Don't be afraid of the yeasties! Its hard to screw up a homebrew!