I can't be the only Portlander on TFP.. I feel so alone..
First, there are tons of things to do in Portland. I really love it, so unless you give me some interests or guidelines, I'll probably just go on and on about things that aren't relevant to what you're looking for.
Rent can vary a lot, even between relatively close areas. Most of the more expensive areas are trendy or hip, but they have enough draws that they are still nice for somebody who doesn't like that status. Most neighborhoods, especially in SE, have distinct personalities even when their main thoroughfares are 10 blocks from each other. You should be able to get a good general idea by looking through something like the
Portland Mercury which frequently has articles about a specific area.
I think statistically there are more rainy days in Seattle. The real weather adjustment is to how overcast it is here. The rain we do get is generally lighter than rain in other areas, just more frequent. Unfortunately, people here do not know how to drive in conditions they haven't seen in 30 days or more. The first rainy day after summer will ruin many cars. 2 hour increases to your commute are not uncommon on the first rainy day. For your first fall season here, remember that and drive defensively.
As far as jobs, I've always had more luck with portland.craigslist.org than with oregonlive or the printed classifieds. Big job sites like onesnowyowl mentioned should all have search parameters for the Portland metro area (503/971). portlandjobfinder.com is a smaller site but I think it has grown in popularity. I've found promising leads there before.
Try scanning through
http://en.wikipedia.org/wiki/Portland%2C_Oregon for more info, you should find lots of things about the neighborhoods and parks/recreation available in the area. If you have any specific questions feel free to ask, I'll tell you what I know.