I got 15th-21st of Dec as a holiday (need to start/end in London) and not sure where to go with the brother.
I was thinking either Paris or Rome or both.
We wouldnt get into LGW on the 15th till about 245PM from KRK on BA. We could fly out that night on BA or the following morning to Rome and spend there till the 18th night, go to London, hop on the Eurostar 19th till 21st in Paris and back to London.
Or just do 1 night/2days in Paris
or do 15th night/16th-19th or so in Rome and spend a few days in London (brother wants to see a play )
Or go to Paris for about 4 days instead of Rome....
I need to keep cost down, so BA has good fares (incl in CE for my tier points) to Rome and I can priceline both Paris and Rome hotels so that would work out...

Any options? How many days would be enough? What to see/do/taste/etc? Rome, we don't need to go to Pompeii...

My goodness, what an open-ended question.

Have either of you ever been to Paris or Rome before? There's so much to see and you can easily spend weeks in each city. Since your time is limited, you really don't want to be rushing all over the place.

For that reason I would certainly not recommend going to both Paris and Rome; you simply don't have enough time.

I would say that if London is the start and end point, then you should go to Paris and not bother with Rome on this trip. You can spend a few days really enjoying what Paris has to offer and then come back to London at a leisurely pace.

+ 1. Paris, baby!!

Between Paris and Rome I'd definitely choose Paris.

I assume you have not been to Paris or to Rome.
Both cities will be very nicely decorated and jazzed up for the holidays so both are great choices.
You can spend easily a week in each city and not get bored. Both cities has some excellent one day trips if you feel you want to get out for a day.
I would NOT do both cities unless you just want to tell everybody you saw both cities and not enjoy either. During winter you can assume flight delays so take that into consideration.
My choice is always Paris. It is awesome. Tons of museums, parks, cafes, restaurants and just an overall fun city to walk and enjoy. Hotels may be pricey in both places during that period and probably overall Paris is a little more expensive than Rome but not by much. London, even with a better pound/dollar exchange rate, is still much more expensive.
I would read through the France forum and do a search. There are many threads about what to do in Paris.

Just to be awkward I'd say Rome! Both are fantastic cities but it depends on what you are looking for. Rome is more compact and easier to do the sights on a short visit and has the potential for great food. But all depends on what you expect of a weekend in Europe?!

I wouldn't mind seeing both and see the major sites as I usually do, but if there's a lot to see in both, maybe it would be better off just doing 1 of them this time.

I would only do one city. Both Rome and Paris have so much things to see that squeezing them both in week makes no sense. I would go to Paris because it has more things to do in the winter. Rome has a lot of outdoor things which are great for spring or summer but I don't know how it is in the winter. So my choice would be Paris.

Paris!

Although, Rome might be a bit warmer this time of year...but coming from London, you're used to the cold weather.

Guess Im going for both. Was able to change some plans and will have about 5 days in Rome, about 4 days in Paris. What tours are worth while to see? What about good restaurants with local flavor that won't break the bank?

Also what is a nice, affordable restaurant for a birthday dinner?
I want to set them up with toptable.co.uk and get a good price.

That sounds better. Bear in mind it won't be particularly warm in either city, so you'll have to bundle up and won't enjoy long days, but it'll be great all the same. The lights will be magical.