In general I like just a handful of styles - pale ales, IPAs, brown ales, stouts, porters - so what I did was look at a ton of recipes and see which yeast was used most frequently in those styles. What I found was that the majority of the pale ales and IPAs used Wyeast 1056 and the majority of stouts, porters and brown ales used 1028, so I was planning to wash those yeast strains to brew with multiple times. And don't forget that you can use the washed yeast up to a year later, so if you don't brew very often with the same yeast, don't you think you might within a year?
Now that doesn't mean I won't use another yeast, but I think I can get by with those 2 strains in most of my beers. Maybe that doesn't apply to your tastes.