1) The city of Seattle or the "west side". This area is increasingly dominated by Amazon, local startups and engineering offices for Bay Area companies like Facebook and Google.
2) The cities to the east of Lake Washington (Redmond, Bellevue, Kirkland) or the "east side". This is the domain of Microsoft, Expedia, Concur and a smaller set of startups.
Most of the intense change has occurred in Seattle and specifically in the South Lake Union area where Amazon is located. Yes, there has been change and growth elsewhere, but nothing that I would consider alarming.
I'm personally optimistic that Seattle will find a balance between growth and continuing to have an enviable culture and cost of living.