The easiest one I've used is the one I put on Julie's laptop, Crunchbang. It's a debian-based distro. It's extremely straight forward, reliable, and since it's not exactly "bleeding-edge", you don't have to run updates daily. (Although, you can and probably should)
In fact, debian based distros are typically straight forward with encryption as well, now that I think about it. My laptop was running Arch, but I decided to opt into using Crunchbang++ because you can encrypt with LVM pretty easily. If you ever get bored one day and want to mess with distros, I'd highly recommend looking into crunchbang++, Fedora, and even debian itself. They're all pretty simple to put together. I'd recommend staying away from Arch Linux, just because you have to install things yourself.. It's very reliable, but setting it up is always a problem for me, because I always forget to do something. Although, I can say this, if you can get Arch installed and up to what you want, you'll never have problems again lol
On the topic of ubuntu, it's definitely easy-mode to install / maintain, but I've never been much of a fan of the philosophy behind it.. Although, It's one of the best for running servers with though, it's how I used to run my bots/scripts on a VPS lol
