UPDATE: So I now have the SSD (Crucial MX300), but I can't get it to boot from / install OSX onto that drive. I open Recovery Mode, but only my standard HDD shows up as an option. The SSD appears in Disk Utility, so it's definitely 'there', it's just not registering as an option to install OSX or boot from. The drive is already formatted as Mac OS Extended. Any ideas how to get it running? ORIGINAL: As per the title, my iMac drive died recently, but considering the machine is otherwise fine I'm hoping to at least keep it running until they refresh the iMac line-up. So I'm thinking of just booting directly from an external SSD, and was looking for opinions on a good medium sized SSD (500gb or so) that'll work with a 2013 (Thunderbolt 2, I think...?) machine. Perhaps more importantly, can anyone talk me through the actual pipeline for setting up OSX this way when I don't have an install disk, nor do I even have a bootable drive? I assume I do the online recovery mode boot-up, but I'm a bit hazy about what happens after that: will I just select my new external drive in Disk Utility and then some option will appear to re-download OSX for it?