I'm going to make this super-easy for you. It all depends on your project, right? So break down your project. Answer these questions to figure out if you should hire a designer or not:
- How motivated am I to learn to design my own website? (be honest because it may take 2 hours to figure out how to position a banner ad) and is it intrinsically worth it for me to learn this (i.e. will I use it again/is it good for me to know)?
- Is this going to be a user-interactive site (i.e. game, social network) or it information/content-only (i.e. blog, business information site, FAQ, reviews)?
- Am I willing to spend more than $5000 on this? (obviously some designers will work for less, but let's be serious, if you're thinking about hiring a designer, it better be because you believe it's going to be worth this much)
Otherwise, Squarespace is the best thing I'd found so far for beautiful web sites. There's a ton you can do with the basic platform (if pricing is an issue), and if you want to insert code, easy. Or have no clue what "code" is, you can still make an awesome site. You can get a free trial here.
Good luck with your site, and feel free to leave a comment or send over an email if you have any questions. I've got a lot of tips on tools to use for things like newsletters, video help, software, code clips, more tools used by professional bloggers, vloggers.