Picking up on the post below ...
If Seattle lands NBA and NHL franchises, it would join roughly half (remembering two MLS teams in LA, and depending on how you do the counting) of the MLS markets in hosting the four other major-league sports:
Here's how the other MLS markets share their territory:
Four other major pro sports:Chicago: NFL, MLB, NBA, NHLColorado: NFL, MLB, NBA, NHLWashington DC: NFL, MLB, NBA, NHLDallas: NFL, MLB, NBA, NHLNew England: NFL, MLB, NBA, NHLNew York: NFL, MLB, NBA, NHLPhiladelphia: NFL, MLB, NBA, NHLToronto: CFL, MLB, NBA, NHL
Three others:Houston: NFL, MLB, NBALos Angeles: MLB, NBA, NHL
Two others:Vancouver: CFL, NHLKansas City: NFL, MLBMontreal: CFL, NHL
One other:Salt Lake City: NBAPortland: NBAColumbus: NHLSan Jose: NHL (Although San Jose moves into the three-other team category San Francisco as part of the market; and four-other team category if you include Oakland.)
One interesting -- though both subjective and speculative -- question is whether Seattle could become the first five-sport city where soccer isn't the fifth sport. I think it's safe to say that's the case in Chicago, Colorado, Washington, Dallas, New England, and even Philly (which seems to love its Union but loves its other teams more). The one city I'm currently uncertain of is Toronto, where I don't really have a good idea of the pecking order. (Argonauts draw about 20,000, I think, and where the Buffalo Bills have been dipping their toes in the water.)