There was an old thread on this but as it was over 10 years old I've started a new one. I'll start it off by saying I've just stayed in one of the Prestige Suites at the IC in Marseille - easily the most impressive Suite I've stayed in! It was approx 115 Mē with ceilings of 6-7M high and floor to ceiling opening windows overlooking the Vieux Port and the Notre Dame. Extremely well thought out layout with excellent fittings including all electric curtains and Porcelanosa bathroom fittings. Much more impressive than say the Pen in Shanghai - no little delivery hatch though!
http://marseille.intercontinental.co...ge-suites.html
Second best is a tie between either Villa 501 at Sugar Beach (formerly the Jalousie ) in St Lucia - just loved the all white decor which complimented the colonial inspired design and the views from the plunge pool and terrace are to die for - or our corner suite at the IC in Sydney, well appointed but what made it was the views of the full harbour right round from the Bridge past the Opera House out to the east.
Best room would be the Park Hyatt in Siem Reap - loved the layout and decor. Others such as Oriental Bangkok, MO HK, FSs Budapest and Bosphorus may have been nice and had great views but for actual room the PH is the one I think was the best.