Buy or Build external HD

External HDs are relatively cheap.. Futureshop has LaCie 500 GB USB drive for $129. I am keen on Firewire and those get a little pricey and hence considering building one with enclosure.

What are the considerations I must know before deciding?

For one, if I make one with encl. I know I can change the HD anytime in the future?

But at times, the encl. are with fans (noisy) and heat up? They don't even have the aesthitics at times.

Some ideas are welcome

I say if you buy a internal one and put it in a case, you would get more for your money. You can always switch the Hard Drives out, like if you had two internal drives, and one enclosure you could switch the two out as you needed.

Hope I helped!

I think this depends on your aptitude for working with computer parts and how much you enjoy or dislike this sort of thing. It is always fun to build your own stuff as long as you are ready to undertake the flip side of that coin - debugging it when it doesn't work!

If you buy vs. build, you know it works. If it doesn't you can take it back and replace it. If you build it, you have to be ready to tinker with it to get it to work the way you want.

Things to consider - speed, speed, speed. Make sure you match the speed of the hard drive interface to the speed of the interface you are connecting it up to, so as to maximize performance. For example, don't hook up a slow parallel ATA interface to a FW800 interface. You will leave lots of unused bandwidth.

Noise. A noisy hard drive can drive you (pun intended!) to distraction. Look at the noise ratings for the drive you are buying. Various measures are used, but you want one with idle sound pressure in the 2.0-2.4 bel range. This is nearly inaudible.

Heat. You will likely need a fan in the enclosure. Make you get a quiet one of these too. In general, check out the specs and make sure you get something that idles in the 17-20 dB range. A gentle swoosh sound at best. Again, nearly inaudible. Both Nexus and Papst make excellent low noise fans.

I'd say go for a external drive by a reputed company like WD. The enclosure thing always has its quirks with loose cables and improper cooling. The company made ones are also a tad bit faster and have some features like automatic backups and such...