In general, I believe the best areas are the those that are attractive to rich "gentiles" (which also happen to be the most expensive on a price per square foot basis).

For example, I love the Yalecrest area (if I were rich enough, I'd own a house on Harvard or Princeton Avenue between 13th and 15th East). Such a beautiful, walkable area.

Olympus Cove and Federal Heights are also pretty nice.

Along those lines, I think the best general area along the Wasatch Front is Salt Lake county north of 72nd South and east of Highland Drive (and yes, I know this includes the U of U but it's still the best area to live along the Wasatch Front IMO).

I also really like some of the nicer areas along the Wasatch Back (which have the advantages of being close to Wastach Front services without as much traffic or pollution, plus cooler summer nights). The downside is driving back and forth in those canyons in the winter.

The St. George area, while nice from late October to mid April, is just too hot and dry for me (and I actually prefer to be in a cold place during the holiday season).

Cedar City is a pretty good town (and near a lot of scenic areas) but a bit too "country" and politicially conservative for my tastes (despite having a university). Same could be said for most of the small towns in central Utah (e.g., Sanpete County, etc.).

Anything in eastern Utah is too small and isolated (e.g., not enough nearby services, etc.). Plus, many of those towns are just ugly/trashy.

Far northern Utah (e.g., Cache county) has too much winter.

Weber county just makes me think of Ogden.

Davis county just seems meh.

And I don't really get the appeal of northern Utah county and southern Salt Lake county. The area is just growing way too fast without the infrastructure (road system) to keep up. Plus, it's just too highly concentrated LDS for my tastes (as is Utah County in general - you know what they say about Mormons being like manure).

Obviously, these are just my opinions and different strokes for different folks.