If you do any sort of traveling a few stores to check out that have really nice, stylish suits, at really decent prices are; Topman, Inc International, H&M (UK, stuff here sucks), J.Crew, Express Design Studio, Calvin Klein, Perry Ellis and Zara (doesn't matter where, they have nice suits here at the Chinook location), there are other stores but these are the ones I can think of at the top of my head.
Also with these places they usually don't have their own tailoring services so you'd have to find your own, soo find a good tailor and know what can and cannot be tailored before purchasing a suit.