Depending upon your budget, and if business is your first priority, may I suggest the Marriot near the airport? No chica fee, but you and your chica must be presentable and discreet. Far from the Gulch ($10.00 cab ride), but it's a business hotel with a recognizable brand that won't freak out whoever handles your expense account.
If you're not too worried about appearances, I go with Irish Drifter; the Presidente is just fine. Business center, WIFI, nice rooms with U.S.-style amenities, and reasonably priced. Yes, you'll encounter gringos and putas, but thanks to the Presidente's dress code, none of the hookers will look like sluts.

You can always pass off the hooker presence... "Well, Jim yes those apparently are prostitutes. Frankly I've never paid much attention. Now about this proposal...."
