Another External Drive Topic

[Pyrotechnic]

Apologies if this has already been discussed. I am sure it has but this forum seems to move so fast.

I am looking to get an external drive for my upcoming iMac. However, I have a few of questions.

1. I presume the drive stays attached to the Mac all the time so that Time Machine can backup when required. If so does the external drive have to be a powered one, as opposed to one powered via a USB or firewire alone?

2. What size (eg 2.5 or 3.5) is the best option and does it matter?

3. There seem to be so many about I am struggling to grasp which are ideal. As this is likley to be on show, I would like a nice looking one?

 

[Pyrotechnic]

OK, its a few hours since I posted this and I am looking at getting a Time Capsule to replace my Router and solve the External Backup problem.

Im curious as to how much this will slow down my Mac if its backing up at certain times ?