Hmmm... my favorites are all northwest destinations.
Homer, AK is one of the most beautiful places on earth, lots of kayaking, wildlife tours, hiking, fishing, and good eats up there. I believe you can also get a helicopter tour of the glacier across the bay from the spit...
The San Juan Islands in WA state are magical and relaxing. Kayak, go crabbing, catch a whale-watching cruise, tour a lavender farm and sample the lavender lemonade and cookies, sail, rent one of Suzie's Mopeds and boogie all over the island, visit local wineries, take your bicycles and island-hop for free on the ferries...
But the low-budget option we tend to pick the most often is a simple camping trip to mountain-lake destinations. We love to canoe, swim, hike, mt. bike, and just hang out in front of the campfire, under bright, beautiful stars.