The domain name you pick isn’t that big a deal, most people will simply add your address to their contact list and bring it up by your name. They might have to type it in the first time, so don’t make it too long. I prefer a made-up domain, if you decide to let friends and relatives use some of your allotted mailboxes they’re not mistaken for you, e.g. if you want to share the service with your niece, jenny at chutesandladders looks better than jenny at johncsmith.
A few random things to watch out for:
Trademarks, domain name disputes - If the name is similar to a trademarked name, e.g. eddiecbauer.com, the company might try to take it away from you. There’s a band out there with the same name as one of my domains but luckily I registered mine way before they were formed and they’re not rich and famous enough to come after me.
Read the service’s legalese carefully, some of the cheap ones will register the domain under their own name and later demand a hefty sum if you decide to move to another service. Make sure you become the domain’s owner and you can get the AUTH codes easily for transfer.
You don’t need to spend a ton of money but don’t go too cheap either, from a very quick glance, it looks like the basic service from Hover gives you just a couple of forwards, i.e. you still need to keep a real mailbox elsewhere, either your ISP or gmail-like. Pick a service package that gives you at least a couple of mailboxes and a bunch of forwards. Also a super cheap service may get too popular and fall behind on support, or even drop some messages.
Not too important but it’s better to use a service hosted in your own country, this way you’re not subjected to the laws of multiple countries.
Hope this helps.