It depends how much 2nd floor work you have.
If it's loads then get a 25.
If it's just a bit then get a 22 with 2 extensions (if you're going to add 1 extension, you may as well add 2.) As has already been said it's a bit of a faff and it gives you even more reach.
The best alternative is a 22 and a 47 Xtreme.
Personally, I can't be bothered with anything higher than 2 floors, these days! What am I like?!