Numbers look pretty good for your region based on ROI.

http://www.remodeling.hw.net/cost-vs-value/2014/pacific/

Here is a link that might be useful: ROI for remodeling projects

Have you checked your insulation? Insulation makes a bigger difference than windows. You can always replace or repair broken windows. I went through the same process in the Chicago area. New windows are great but it wont substitute for poor insulation.

You can choose from lots of different brands. For vinyl i recommend Simonton, good window with good warranty Or PlyGem cheaper and also you can have triple pane glass for really good price.

I agree with Carolmka, caulking and insulation. The payback in terms of energy savings for new windows is a recovery period of something like 20 years depending on energy costs and window prices.
Talk to a realtor as far as an increase in resale value. but if you are doing this for energy savings, do the insulation first.