You have two options.
1. Fresh OS install
2. Migrate an image of your OS HDD to your new SSD
The first option seems like the easier option but you have to factor in the amount of time you'll spend installing all your drivers, windows updates, and applications
The second option is, IMHO, the better option. You first prep the drive by aligning it. Then you run disk cleanup, ccleaner, and finally defrag on your HDD. Then you use a program to clone your HDD to your SSD. Then you swap out the drives and have fun with your new SSD.
Now I made option 2 sound a tad bit simpler than it really is, but it's not hard at all. This guide
is fairly straightforward and easy to follow and works great if you're going with option 2.
One tip, though, is when you get to one of the final steps where you clone the drive the program will show you one final screen before you actually do the cloning. You'll see a colored bar for the source HDD and destination SSD. Click and drag to shrink the System Reserve partition in the SSD bar to as close to 100mb as you can but don't go under(hover over the sysres partition to view what size it is). For some reason this program tries to make that partition like 9gb which is unnecessary. You can fine tune the size of that partition to the recommended 100mb later on with Windows Disk Management but this will create unallocated space to the right(to the left of your primary C: partition) which will require a third-party partition program to allocate to your primary C: partition since Windows can't.
Then there are the list of tweaks to perform so you can optimize windows for your SSD. Disabling superfetch, prefetch, bootfetch. Disabling disk caching and enabling memcaching on firefox. Moving the file cache for firefox/chrome/etc to a secondary HDD. Enabling windows write-caching. Disabling certain windows logging. Setting search index to cache its files to a secondary HDD. Disabling disk defragmenter(you don't want to run this on an SSD!!!). Etc. It's up to you how many of these tweaks you want to use and most good guides will warn you if any specific tweaks have any downsides. The whole goal here is to reduce the amount of writes to your SSD and reduce the amount of garbage files that pile up on it since space is an issue. There are also ways to place your user folders and other windows essentials on a secondary hdd and map windows to their new locations, just another way to free up space on that ssd.
I just did all this yesterday with my new 60gb OCz Vertex. Win7 64bit with chrome, firefox, and a bunch of other programs(even a full-on rainmeter theme) and I'm sitting at about 30.5gb of space used. I performed most of those tweaks and have all my caches, indexing, pagefile, etc using my secondary raid-1 HDDs.Edited by johnny.dot.exe - 7/24/13 at 4:35pm