Step 1 - get the Premier CC, there's your Marriott Platinum. The $65 is also buying you bonus points and a Free Night certificate, so even if the Gold-Plat bump is worthless to you (which it kind of is outside of the FS properties), you're still coming out ahead.

Step 2 - you have a Hyatt vs. Hilton decision to make. I don't have a whole lot to add that others haven't covered. Ten years ago, when I worked for that same global consulting firm that I'm guessing you do now, I was a Hilton guy all the way. But since 2000 or so, I seem to travel most often to weak HH cities and strong MR cities, so I switched to Marriott. Hilton Diamond seems to be popular among FT'ers - your earning power on paid stays is higher than anywhere else, and you get Starwood-like availability rules. As a HH Gold, I have a more difficult time getting awards with Hilton.

I don't know much about Hyatt - other than the fact that it is appears to be a lot stronger at the full-service end of things, whereas Hilton is more distributed across the service spectrum. For both rural and suburban locations, you'll find a lot of Hilton choices and little or no Hyatt. For big cities, the best Hyatt will probably outshine the best Hilton.

(To answer someone's other question - yes, the global travel agency for this particular consulting firm frequently extended elite-comps to people who were on the road every week. I recall at one point they sent me unsolicited Northwest and Delta mid-tier elite cards - apparently right after they reached a corporate discount deal with those airlines. I was mildly annoyed at the time - fearing that the comp had "burned" my once-in-a-lifetime comp that most airlines will give people. Since ATL, MSP, DTW, etc. were never in my travel plans, I never used the statuses. I confirmed with the travel agency that this was a true free comp - not one that burned my account for life - although I haven't actually tried for a comp since.)