My i3 iMac is getting increasingly unreliable and I am thinking about getting a Mac Mini. I was thinking about getting one of these Mac Minis. http://www.apple.com/shop/product/FGEM2LL/A/Refurbished-Mac-Mini-14GHz-Dual-core-Intel-Core-i5 However, I would like 1TB drive because I take lot of photos with my DSLR in RAW format. Any suggestions on an affordable external drive? Thanks.