gogreen: There are several schools of thought on defragging and the latest is that the NTFS file system does not require as frequent defrags like the fat file system. Back in the days of FAT file system 16/32, it could really slow files access as your files were scattered all over your disk.
I personally use VOPT by GoldenBow systems when I feel the need to defrag as it is faster and I believe it is more versitile.
Don't get paranoid about defragging as once a week or once a month should suffice.
that program puran defrag seems to be versitile but I have no recommendation for or against.
The built in defrag in windows 7 is a bit slower but it will do the job.