Of the other hotels that you mentioned. I'd be careful with the Westin St Francis - there are lots of negative reports of getting stuck in a small room if you don't have Starwood status. I think that the IC & Fairmont might have similar issues since they are both also older buildings. The GH's rooms are much more uniform since its in a newer building. Corner rooms feel quite a bit larger. I've always been in an RC room and normally in one of the corners.

At the GH:

Business Plan - simply denotes the inclusion of local phone calls & continental breakfast - I believe that any room can be made into a Business Plan room.

Regency Club - gives you access to the club lounge with continental breakfast and hors d'oeuvres.

Hospitality Suite - I'd avoid this for a "normal" stay - I think the setup often has a foldup bed and generally used for entertainment by companies.

Executive Suite - a regular suite - never been in one in this property.