Rome sucks, see what you want to see as quickly as possible then go somewhere else in Italy (Florence, Venice, Naples, whereever). Check out the Vatican, in Rome, it is the best deal you can get, to enter the Basilica of St. Peter it's free, the Meuseum costs about 8 Euros and has tons and tons of great art and historical artifacts (including the Cistine Chappel which is incredible). Do not go inside the Collouseum (it's 10 Es and not worth it at all). look at it and then go check out the ruins around it, it is a waste of time, don't bother with the Roman Circus, its a big patch of dirt for the most part. Also it is really really hot, take your own water because it is expensive to buy it on the streets. If you are travelling with lady friends, keep them away from the dudes who sell the purses, they are rip offs and if they see your interested they do not stop harrassing you.
In Spain, go to Toledo and Salamanca if you can, great cities, and if you go to Madrid check out a restaurant called "El Botin". It's the oldest restaurant in the world, and the food is fucking delicious.
I don't France, so your on your own for now.