When I come across situations like this, I use the task manager to figure out what applications are using the most handles, and I quit them if I'm not actively using them.  MySQL is a big offender, I've found -- I'm not sure how a database engine that has about 3 MB of data in 20 tables, in one database, can somehow manage to use 4,500 handles, but it does...

Obviously, this isn't really a solution, but it may help a bit.