You want to clean house from time to time with Gimp. The more things you have installed (fonts, brushes, patterns, scripts, plug-ins), the slower Gimp will be in loading upon start-up.
Here's a few tips on cleaning up your hard drive and speeding up Gimp:
Dump your thumbnails file (C>.thumbnails or C>Users>Name>.thumbnails). Simply delete the contents of the folder "fail" and "normal". Sometimes "normal" may be 100 megs. You can change this with preferences too, this just seems easier for me.
Speaking of thumbnails: If you are using ACDSee, you can clean house by deleting the ddf file, which can get quite large too. All it does is store thumbnails. When you visit that folder with ACDSee again, it may be a little slower to load but you have cleaned up HD space, making other parts of you computer run faster. Also, if you have deleted a series of folders, those thumbs are still stored here and are not needed. You can find this by having ACDSee open, clicking on options then the miscellaneous tab and under image database there will be a path. Open that path in Windows until you locate the ddf file (mine is C>User>Holly>App Data>Roaming>ACDSee Systems>ACDSee). Close ACDSee before deleting.
Empty the Recycle Bin so you computer knows it has that space available. If you don't empty it, then that stuff is still sitting there taking up space. After dumping the RB, the info is still there but the computer knows it can write over it with something else and shows it as available space on your HD.
You also want to remove brushes and patterns that you are not using. You don't have to delete them, just move them to another file. I actually burn mine to a disk and just delete them off my HD if I'm not using them. I know whatever is in my .gimp files I can just delete. Those that are not backed up yet are in a file My Dox>GimpTools>To Burn, so I know these need to be copied. When I make new patterns and brushes I copy them to the "To Burn" file immediately so I can have them for later and I don't forget.
To go one step further, you can now clean out your temporary internet files and if you haven't in a while, defrag your baby too. All of this makes every program you have run faster, not just Gimp. About 2-4 times a year you should clean your computer. If you are not comfortable doing it yourself, spend the money and bring it in. Some shops have discounts for regular maintenance. Sometimes cleanings are under your warranty, read your small print or call the store to find out. A tower full of dust bunnies will run hotter, using more power and running harder, in the end slower. The only thing fast on a dirty computer is the time that comes when the computer quits. I don't recommend cleaning it yourself because static electricity can zap a computer and then all you have is a paperweight. ALWAYS back up your stuff before cleaning the insides of your tower. I will do my own tower but I have my laptop done at a shop. Don't forget to clean your mouse and keyboard. A sticky key on my friend's computer happened to be the F10 key, which upon reboot put her into system restore. She lost everything.
Lastly, to make Gimp start up better, always shut down Gimp by using the File>Quit option instead of hitting the little x's. The little x's is almost equivalent to a hard shut down or a crash.