The Holiday Inn at Moskovskye Vorota is a modern facility with ok rooms but excellent facilities. It is a bit outside of the downtown sightseeing areas, but it is also an easy walk (even in the February cold) to a metro station, and then 4 stops on one line to get to Nevskiy Prospekt where the sights begin.
The rooms aren't anything fancy, but they are clean and have the normal amenities you would expect. There is also a supermarket in very easy walking distance if you want to buy snacks/water/etc. at "non-hotel" prices.
There are several restaurants and bars in the hotel building, I tried several of them during my 4 night stay and I found them all to be good to excellent (Korovabar was my favorite). The hotel had decent meeting facilities as well, so if you're organizing an event you can do it and do it well in one contained facility.
If I was staying in St Petersburg for tourism, I would probably look for a hotel closer to downtown. But I would also not rule out the Holiday Inn at Koskovskye Vorota, as it is reasonably-priced and an easy place from which to get out and relatively easily explore the city.
- Holiday Inn St Petersburg
