We are going to Lake Como at the beginning of September, will be staying there for 4 nights. I have the following options for stay.

Hotel Du Lac, Bellagio - mini suit on top floor, lake view from terrace
Albergo Lenno, Lenno - lake view room, no balcony
Hotel Darsena - side room with lake and road view and balcony.
Which one to choose? We are looking for a hotel on the lake, lake view, preferably with balcony on the lake, not noisy, comfortable accomodations.
Would love to hear from people who stayed there to understand the real level of hotel, beyond the facade.

La Darsena is right on the lake (most hotels are across the road from the lake), but right up against the road as well. It generally gets good reviews. Hotel Du Lac is in a good location and Bellagio has lots to do in walking distance, while Lenno and Tremezzo are somewhat more limited.

Definitely Bellagio and I think Hotel Bellagio has even better views than Du Lac (make sure you ask for a front room with balcony). Du Lac is opposite the ferry dock and could be a bit noisy. http://www.hotelbellagio.it/indexeng.htm

The Hotel Florence is next to the Du Lac and is a better hotel IMHO. I assume you will not have a car. Lenno can be nice but a bit isolated compared to Bellagio.

I listed hotels that have availability, hotel Florence is fully booked.
We will have a car and that's why i was considering Lenno.
Does it make a difference for the rest of the hotels?

Yes, a car can be a real hassle in Bellagio. Just getting there is not easy, and parking is hard to find.
I would stay on the west shore. Lenno is a good choice but so is Menaggio---I love the location of G.H. Menaggio, and the Hotel Bellavista.

I recommend Hotel Metropole Swiss or Palace Hotel in Como.
Lots to do and good starting point for the rest of the surroundings.

Like Bob, I favor the idea of staying in Menaggio or Lenno if you have a car. Menaggio has the advantage of being on the main ferry lines, and it's right off the main road with easy access to Lake Lugano and other points west (if you're so inclined).

We stayed at the Bellavista (***) several years ago. The views were stunning, but if I had to do it over again I might spring for the 4-star Grand Hotel Menaggio.

We enjoyed our stay at Hotel du Lac in Bellagio -- great views, near everything; has an aura of shabby gentility unless it's changed in the several years since we stayed there.

We have since moved to apartment living in Bellagio -- if you have any interest, both La Limonera and the self-catering apartments at Villa Serbelloni are ones where we've stayed. La Limonera is charming and central; Serbelloni includes access to the villa amenities but might only rent by the week.

There is parking next to the church on the upper road in Bellagio. We were told by our landlord to park there contrary to what the sign says.

Have stayed at the du Lac (and the Villa Serbelloni). Great location and very comfortable rooms (this was several years ago and some had been redone, others not). They had access to a garage up the hill from the hotel where we parked-extra charge). Very warm, friendly family run hotel. We enjoyed the ability to use the Bellagio Sports Club facility which was 10 minutes away with hotel shuttle.

Thank you for all your suggestions. Decided to take a room at Du Lac. We will stay there for 3 nights and then will take flytolake shuttle back to the airport, pick the rental car and drive to Stresa for one night. Should get there in the early afternoon which will allow us to see at least one island and may be see something next morning and then off to Ligure. Does this plan sound ok? I am not a fan of one-nights but there is no good connection between Lake Como and Maggiore to make it a day trip.
How do people move around lake Como when they don't have a car? How to reach Villa Carlotta? How to reach the restaurants? I read that ferries stop running in the evening. What time exactly? Are limited to Bellagio for all our dinners? What are recommendations for Bellagio dining? It'll be my husband's birthday, looking for a special place.