[competentone]

Buy what's out of favor now; leave it as it is; in ten years when you sell, it will probably be the style everyone wants!

Seriously (although the above comment is not really un-serious), there can be a LOT of variables that would affect the answer to your question. We'd really need pictures and drawings of what you've got and what you want to change it to before being able to give answers about its feasibility.

Generally, the rule applies that it's difficult to do renovation work on a house and get your money out of it, so you should normally only do renovation work because YOU want the changes, not because it will affect the house's marketability. (With the real estate boom, this "rule" hasn't applied in many markets for the past few years; if things are settling down, it will likely be the situation again.)