I literally refi-d mine two days ago. Here's how it broke down for me: On the plus side, my interest went from 14.5% to 7.5% due to better credit situation, and payments went from $460 (51 remaining) to $340 (48 months). Needless to say, it was well worth the down sides. And here they are: First, it creates an inquiry. Despite a heartfelt attempt, I couldn't find anyone willing to base a credit decision on my own copy of a bureau; they have to do their own hard inquiry (SOP for most, if not all, anymore, I guess). Second: it lowers your average age of accounts, as this is considered a new account, regardless if the old one is closed or not.
Having asked the same question when in your shoes last year, I'll pass what the pros advised; hold off on ANY new inquiries or accounts if at all possible. The one exception that could come to bear would be if you need to free up cash for a better D/E ratio, then I could see weighing that decision carefully (any pros want to help out here?).
Just a couple words from someone who's been there. Hope it helps, that amount should buy a beautiful home! Good luck...