Though I am quite the guerilla tourist at times (travel fast, see lots of stuff), I think 10 days may not be enough. You'll spend more time traveling than exploring the cities. I would suggest to pick 2 or 3 that you really want to see. These cities are mostly very large with tons to see. I would pick a place and make it special, especially if there is a proposal involved, make that your special place that you can think back to fondly.

I can't really suggest hotels in many of those cities. I've been all over Europe but not Spain... yet. I have been to Rome but my hotel was so-so. It was nice and all, fabulous location but a few things bothered me. Though it may also be that I just don't like Rome much. In Paris, I love the Montparnasse area. I usually stay at the Lenox Montparnasse which I love but their prices have gone up a bit lately. I'm staying at the Aviatic St Germain this weekend and their prices and location are great. I can let you know what I think of it after my stay if Paris stays on the agenda.