If you have a better suggestion for an external hard disk enclosure please let me know.
I want 250 Gb of free space but I wouldn't mind more, who is making hard disk drives and who is making good ones?
Also I am looking for advice on installing the hard disk drive to the enclosure do I have to partition or format the hard disk drive after installing it?
That enclosure looks fine, but it all depends on what kind of hard drive you are planning to hook up, and what type of connection you would want to use to connect it to another computer.
If you are going to use USB, then there are tons of enclosures available. If you want to hook it up via firewire, then check those out. If you've got a relatively new mobo, you can check to see if you have an eSata port (these have almost no bottleneck when transferring).
There are so many hard drives available to check out. I'd check the various models by Western Digital and Seagate. These are some pretty good companies that offer 5 year warranties on most of their disks.
If it were me, I'd check into something at least 500gb - these only cost about $100 (maybe 110) right now.
You don't have to partition, but I definitely would. I put together an external HD a few years ago and partitioned it for separate things (backups, documents, music, photos, etc).
So....check out newegg.com. Check out the best selling and the most popular external enclosures. Be careful that the connection in the enclosure matches the hard drive (IDE or SATA). I would suggest getting a SATA enclosure and HD (ATA is the old standard, but works OK still). USB is pretty standard, so that's usually a good choice for the enclosure as well.
Then check out the various hard drives of 320gb - 500gb. Like I suggested before - check out SATA - it's the current standard for the most part.
Once you get it, it should be easy to put together (honestly it's only a few simple steps). Once you have it together, plug that thing in, partition it how you want, and you're off and running.
I personally do not like the external enclosures with a crappy 4cm fan in the back, I have owned two units with that type of fan and both have started to make noise, to the point that I stopped using them.