I am looking for nice looking sites that are good in terms of look and feel as well as usability.
Someone had to say it: Stack Overflow!
Seriously - it may not be immediately beautiful to look at, but for what it is, and for its target audience and how they use it, it's a great example of both visual design and interaction design.
The layout, the use of colour, the sensible use of AJAX, the lack of fancy graphics, all give a good experience IMHO.
It's also a good example of how to incorporate advertising in an effective but unobtrusive way.
Zen Garden - beauty but especially showing you what different things can be done with pure accessible HTML. So having Usability in mind as well.
I think this is question is much like http://stackoverflow.com/questions/1059913/share-good-examples-of-web-guis question that was post in the site sometime ago. probably it will help you.
Google.
It gets out of the way as much as possible and lets you focus on doing what you came there to do.
I've always found that other people's great web sites are more of an inspiration than a practical help. Every site has particular needs. For example, this site is good for what it does, but it really isn't a site I need to build; likewise for this one and this one.
I think it is valuable to develop a philosophy/aesthetic for this, or at least be conversant with those who think a lot about design and accessibility. Here are two sites with some serious discussion along these lines, along with some coding howto:
But even these reflect my personal taste. There are people in my family who really like Club Penguin. And I hear some folks can tolerate MySpace.
I don't know what kind/segment of site you want. But I`ll mention one that is kind of site to create site that helped me to create fast and beautiful things.
www.snappages.com is a example of nice/easy/friendly/pretty/dummyFriendly/niceExamples/easyToCreatePrettyThings/easyToMaintain/etc...
I really think that is a 'must know place'
Cheers :)