Next two are tougher call, but probably Arizona St and Colorado. Large markets and better geography.
You could make arguments for a bunch though for those last 2
Utah is currently the strongest at football and brings the best viewership, plus a high profile rivalry
Colorado brings Deion, Denver (kind of) and Big 12 history
Arizona St brings Phoenix and some sort of SW access maybe?
Stanford/Cal have huge market, access to California and elite academics (plus Stanford draws decently)
The ones I wouldn't take care Arizona (basketball is nice but otherwise weaker), Washington St (surprisingly decent viewership but market/geography is a nightmare) and Oregon St (just not on the same level and limited upside)