External Hard Drive for backup...Time Machine?

I just bought an external hard drive (My Passport for Mac) because my Macbook's hard drive is almost full. I did not want it necessarily for backup purposes, but rather I wanted to be able to store music, docs, etc. that I might want to access in the future, but want to remove from my computer for now.
Should I use Time Machine? Will time machine let me access my hard drive to obtain certain files when needed? Or is Time Capsule's sole purpose to backup everything on my computer?

I would not use Time Machine but copy the stuff you want over to the Passport external. I would suggest you also get into a backup mentality and buy another separate drive to use for your Time Machine backup.

I have read quite a few times where the Passport drives fail randomly so IMO I would not use it for TM but they excel as easy to carry portable drives.

Be safe and get into the backup mentality. It has saved me numerous times as things get deleted and / or drives fail.

Just remembered, I also would format the Passport from your Mac before you use it. This way you know it is Mac OS formatted and not from the factory (which is usually FAT32) that works for Mac and PC.

Depending on the size of your external and how much storage you require, you could partition it and use one for dragging files to, and one for a Time Machine backup. Might sound redundant but T.M. is great for fast retrieval of things you accidentally deleted or when you need to revert back to the way a file was before you made changes, etc.

back up with Passport - I am new at this!

I used a usb plug in backup thing called 'Passport' sold to me for that purpose by Apple
They backed up from the Mac Laptop.

I now want to install the iphoto files from the 'Passport' to my desktop Mac OS X.

It seems logical to plug the passport into the desktop Mac and choose the file but it tells me that I don't have permission.

Can you suggest the method?