I stayed here:
Hotel Florida .. of course, it doesn't compare with what I'd expect most anywhere else in the world, but it wasn't too bad. Great location. Didn't get to trying a Casa Particular (staying in someones' apartment), but that's supposed to be pretty awesome as well.
All good advice so far. Agree 5 days isnt enough!! We managed to fit Cienfuegos (sp?), Trinidad (Iberostar hotel there was quite modern) and Havana into about 7 days. Could have stayed 7 months if i'd been able!
Note we also stayed at the hotel mentioned. Great location. Easy walk though "old" Havana.
A couple of issues:
1. There's more than one "hotel florida" so unless transport arranged directly with the hotel or a tour company, beware the taxi driver takes you to the right one. Ours dropped us off down near the waterfront, whilst Havana was under curfew (post cyclone) and said "up there" pointing to a dark, cobblestoned alley. Cue four of us hauling suitcases up a closed street, fully expecting to be mugged by the driver's "friends". He comes roaring back in his minivan and waving furiously to come back down to him. Somewhat panicked, we do so. "Wrong Hotel Florida!!" he tells us in broken english. Phew. "Right" hotel Florida located and checked in (around 2 am!!).
2. The cleaning staff stole various (non valuable) items from our luggage. Mostly soaps, perfumes, and some mini koalas (clip ons) we had broght to give away to local kids etc. Hotel staff useless in dealing with complaint, and seemed no point making police report as the overall value was less than required to make a claim on travel insurance - it was more the annoyance. After two nights in Trinidad, you should have seen the cleaning staff hiding from us when we were back there for our final night prior to flying out.
3. The breakfast buffet (included in room rate) was appalling - virtually unedible.
Lock your suitcases when you leave your room. Otherwise it's fine for what it is - a Cuban hotel.
I'd also advise to be respectful to the people, who often genuinely dont have very much,but if you're nice to them, will do almost anything to assist you. Beware also that everything tourists see and do is quite closely controlled. Not that it's such an issue, just be aware of this. Some of the better things we saw / did were in our time wandering around on our own. Random tiny clubs with guys playing music etc. Note that most will then try and sell you a CD of thier music afterwards. Not overly expensive and a great souvenir. Ask them to pose for a photo with you (and have someone take your photo with the band).
A 1950's car tour sounds corny, but was actually great fun, and a great way to get about and see parts of the city you couldnt walk to.
Happy to answer more specific questions.