I was planning on buying a new HDD for my computer to put pictures, music, games (legal ones ) on to it as I am currently using a 100 GB external one which has 2 GB free and there is loads more files on my main HDD waiting to be copied over. I know I have the space and cables for an internal HDD in my computer but my main concern is that I do a good bit of gaming and a lot of heat is generated so would the HDD increase this much, sorry if I'am being a bit paranoid, but my old pc died from over heating. But of course the internal HDD has much faster speeds than an external one.
There is only a £7 difference in price between the external and internal hard drive and they are in the links below.
The external drive you've linked to is USB 2.0, which will be a lot slower than an internal drive.
If you want to go external and your computer has a USB 3.0 port, try to find a USB 3.0 drive. If your computer doesn't have a USB 3.0 port, you can buy an adapter card to add one to your system. Another alternative for high speed is to use eSATA.