I would pick either the Florence or the Metropole. Of the two, I've only stayed at the Florence but would recommend it. IMO the Belvedere is better suited for a longer stay.

I don't why Belverdere would be better for a longer stay. We stayed there three nights and loved it. Fantastic lake views. It is located at the top of the hill so you will get your exercise. Plenty of good restaurants near by.

I realize you're not asking for restaurant advice but I recommend eating at the Bilacus (near the top of the main staircase on the right). The food was delicious and hearty portions; staff was so wonderful. There have been many references on this board for the Bilacus (that's where I first heard of the resto).

Here's a TripAdvisor thread:

http://www.tripadvisor.com/Restaurant_Review-g187834-d1228496-Reviews-Ristorante_Bilacus-Bellagio_Lake_Como_Lombardy.html

I second adrienne's recommendation of the Bilacus.

We stayed at the Belvedere and it has awesome views to the east side of the lake. It is a very short walk into the top of the the town, the area we prefer.It offers parking.
The Florence is right on the lakefront, north end, and gets good reviews.
Bilacus is good but on the main tourism staircase; Ristorante Barchetta is a lot better.We have celebrated several birthdays at La Barchetta and it has never disappointed us.

Tough choice !
The walk uphill is the tie breaker for me.
But, the views are super.

I have stayed at the Hotel Florence several times and much prefer it's location to that of the Belvedere. One of the joys of Lake Como is hopping on a ferry and going to the various towns on the lake. It is a bit of a trek from the ferry terminal to the Belvedere.

We (two 60-something couples) stayed 3 nights at the Hotel Florence in rooms #4 and #5 that share a large lake front terrace in May of 2012 and we had a great time. The staff was super friendly and very helpful. Our last night in Bellagio, we enjoyed a fantastic 3 hour dinner at their outdoor restaurant while watching the lake traffic and the sun set.

In my opinion, the old-world charm, the staff, the location and the view from a lake front room at the Hotel Florence are hard to beat if you want to stay in Bellagio. If you are interested, I posted a trip report of our visit to Northern Italy and near the end of it is a link to some pictures we took.

http://www.fodors.com/community/europe/milan-venice-bellagio-piedmont-wine-country-a-day-in-the-cinque-terre.cfm

Just wanted to bookmark this for the restaurant link ...enjoy your stay