I haven't stayed at many of these brands, but I thought it might be worthwhile to compile typical amenities of hotel gyms.
Hilton- Conrad
- Doubletree
- Embassy Suites
- Hampton Inn - Not all have fitness rooms. Those that do have a treadmill, elliptical, and bike. There may be a universal machine and occasionally free weights. Older hotels often have older equipment.
- Hilton Hotels
- Hilton Garden Inn
- Homewood Suites
- Walforf=Astoria
- Hilton Grand Vacations
Starwood- aLoft
- Element
- Four Points
- Le Meridien
- Luxury Collection
- Sheraton
- St. Regis
- W Hotels
- Westin
Hyatt- andaz
- Hyatt Hotels
- Hyatt Regency
- Hyatt Place
- Hyatt Resorts
- Park Hyatt
- Summerfield Suites
..more to come after dinner
Please comment about the fitness rooms and I'll update up here. I'll try to keep this post about usual fitness equipment or offerings. Special hotels can be discussed in the comments.