Where's your job physically? This is KEY.
If you are from the sticks (as opposed to say, Philly) then Bellevue could be considered a small city. Really it's a sprawlingly large "town" with multiple "centers" but Downtown Bellevue is by far the biggest hub of everything. Shopping, food, etc. I think it's fine. Not great, better than lame, mostly more affordable than Seattle.
It is adjacent to Redmond, which is like a shittier version of Bellevue and even more sprawling and poorly laid out. But cheap. Kirkland (near the lake) is a little ritzier than Redmond and the downtown is actually pleasantly laid back and "cute". If I lived on the Eastside, I would live in downtown Kirkland for sure. Feels almost like a beach town in the height of summer. MOST of Kirkland however, is houses, strip malls and freeway exits. And that's IT. It's "cute." It has loads of restaurants, shops and a few boutiques, but there's no culture and the nightlife (in Bellevue AND Kirkland) is cheesy and woeful.
Seattle is obviously the most diverse and "action" packed. World class tourist city, but still pretty liveable. Ain't cheap. If you don't like commuting, or are living on a shoestring budget, Seattle probably isn't for you. Again, depends where you're working. If it's Microsoft, then the free wifi enabled shuttles make it well worth considering.
And there are gorgeous parts of Bellevue and Redmond where you could be by a lake, a mountain, or in a forest.
