Great piece Broonage, it sounds like you had a brilliant time. I was in Rome for 4 days last September and can only back up all the wonderful things you have to say about it. A few points of my own. As others have said Profondo Rosso is not that cheap especially for DVDs but you simply have to go there for the expierience. The museum itself was slightly bigger than I was expecting from the pictures I had seen but is still not massive..definatly worth a look though.
On the first day there I found a street vendor selling DVDs about 2 minutes walk from Profondo Rosso...it was a Lovelockandloaders idea of paradise. He had 3 or 400 films for sale including most of the Alan Young releases brand new and sealed for 3 euros a piece..I was like a kid in a candy store. I bought about 12 films some of which I already had but could'nt resist due to their cool Italian covers. I went back next day to continue shopping but he was gone and replaced by a bloke selling womens shoes, my wife was delighted I was like a demon!! So there is my first piece of advice if you see something you want buy it then and there as it may not be there the following day.
Second piece of advice is regarding accommodation, if you are thinking of going I recommend you stay as close to the centre as your budget will afford. We stayed at a hotel called the Roma Congress in Via Prenestina which was about 6 miles from the centre of Rome. It was a long walk to the metro through an apparantly dodgy area and even though Merli makes it look like a piece of piss I was not in the mood to take on the local hoods! It was 35 euros by taxi as we found out to our cost on the first day so that was not an option. We decided on the hotel shuttle bus at 10 euros a day return but this took an hour and a half each way due to the manic traffic conditions..so be warned. I would have been happy to walk but the wife's feet were killing her after the 10 hours sightseeing each day...serves her right for wearing the shoes she bought from my fucking DVD stall !!!!! Only joking and happy travelling.