OP doesn't say where and that really matters. I tip according to local custom because that is what matters. OP does say that this is a 5-star hotel (not many Sheratons or Westins are seriously 5-star, but lets let that pass :
1. Bell Hop Takes your Bag to Your Room: $2 per bag, but never less than $5 total
2. Housekeeping on a ONE NIGHT (in-and-out) stay $5 per night per room. A one BR suite would be $10:
3. Housekeeping (per night or at end) on a multi-night stay same as one night, but times the # of nights:
4. Housekeeping on a multi-night stay when you do Green Choice (say 5 days using GC. What do you tip at end of stay?) The housekeeper gets the same tip:
5. Valet takes your car $2:
6. Valet goes and gets your car $3:
7. Concierge helps you out Depends on what you mean by "help". Resevervation which you could have made yourself = $5. Reservation at tough place in NYC = $50+:
8. Front Desk person goes above and beyond (scores a great suite, slips you drink tickets, etc.) $20+:
9. Wait Staff when they have already included a 20% tip on the bill Nothing, if it really is a tip, not a service charge which goes to the property:
10. Club Lounge Attendant $5:
11. Server when you are at a buffet (they bring coffee, juice, then bring bill) 10% if that really is the extent of the service
I also increase this accordingly for properties where I regularly stay. Trust me, if you want early check-ins, late check-outs, a primo seat at a tough restaurant, being known as a good tipper matters. And being known as cheap gets you the broom closet next to the elevator.