If you haven't already of course. I have spent a large portion of my afternoon trying to remember my old password in order to get rid of my Myspace page because the email address I registered with is no longer active, as I suspect is the case for lots of people. This is probably the reason I didn't realise that Myspace changed to a (rubbish of course) new layout where all of the customizations made long ago no longer work and look like a car crash, and there was a giant ad for some rubbish band I don't like on the front.
"Why not just leave it there? I can't be bothered to work out how to change or delete it and no one ever checks it anymore surely?". For most regular folks that is true, but for musicians Myspace was the industry standard for a very long time. That means it usually still comes up top in the search engine rankings for your name even if it looks awful, people are clicking on it - get your shiny up to date website up there instead.
"What about my 10,000 friends??" If you're not logging in what's the point of them? Concentrate on growing your e-mail list and actually emailing it - Twitter does a better job of letting your fans speak to you directly and hear your news than Myspace ever did anyway.
Another reason you should get rid is that the long, humiliating, protracted death of Myspace courtesy of Rupert Murdoch means that your profile is being used to advertise things you have no control over unless you buy a premium account, similar to a bot which harvests and parks adverts on the urls of people's names who may one day become famous (and want to buy them back for an extortionate sum).
Once you've hit 'cancel account' 20 times and gone through the rigmarole which just confirms how rubbish and desperate Myspace is, what next? (Either do that or spend hours updating your page, but don't leave it). There are lots of ways to build a decent web presence, but by far the best option I've seen for artists recently is Flavors. Flavors is a website builder which makes simple but beautiful design really easy, and collects everything else you've got scattered about the web (Twitter, Facebook, Tumblr, Last FM gigs, Soundcloud, Bandcamp etc - all of which are great but don't give the full picture) in to one nice looking place. I've been recommending it to my friends so a good recent example of it in action is ericlaumusic.com.
A Few Tips (for non-web nerds)
1.//Whatever the top search engine result for you is, make sure it's up to date. If you don't want to delete your Myspace page, update it then push it down the search engine rankings with a good website, Bandcamp, Soundcloud and your social network profiles.
2.//Whether you are about to build a website or not, register your domain name (url) before the afore mentioned bot harvests it. I use GoDaddy.com for putmeonit.com because they send reminders if your credit card is expiring (instead of just auctioning off your URL as a third party once did to me!).
3.// If you're signing up for Flavors, the pro version at $20 a year is pretty cheap and it's on 2 for 1 at the moment so if you arrange to sign up with a friend you can split the cost and get it for $10 each. Bargain.
4.// Whatever your website looks like, add a newsletter sign up form and USE IT. I've downloaded countless free Bandcamp projects in exchange for my email address and I rarely hear from the people who've put them out. Your mailing list are the people who are going to buy your projects when they're for sale, come to your gigs, blog about you etc - stay in touch. I use Your Mailing List Provider because it's the cheapest I've found, and pretty easy to use. Apparently if you use the code: 02NA2J you get a discount. If you're emailing more than a couple of hundred people at a time use a mailing list provider or your email account might get suspended for spam!
5.// There are lots of website builders aimed at artists out there at the moment but for the most part the services they provide seem to be a bit of a rip off - all you really need is a blog (Tumblr is a winning combination of easy to use and very attractive without customization), a bio page, and links to your music, videos, gigs, press shots and social networks.
Whatever you do, don't leave your Myspace looking like a car crash from 1996.