Larry Cloud of cloud9northwest.com has some recommendations:
1. Best view – Cape Lookout on the Oregon Coast, hands down. Only problem is, to get that awesome view, the weather has to cooperate. Its often cloudy/rainy there, so I’d say the Cape Lookout hike needs to be done in July or August.
2. Best workout – Larch Mountain Crater Loop – you can actually start this down at Multnomah Falls Lodge on the Columbia River and climb 12 miles up the gorge wall to the top of Larch Mountain (we haven’t done this yet though).
3. Best family hike (if you want to bring kids) – I’d say probably the Triangulation Peak Hike is the least difficult and safest.
4. Best waterfalls – Silver Falls State Park. 11 majestic waterfalls within an 8 mile circle. Runner-up would be Ramona Falls. (note: his wife, Ramona, likes Ramona Falls best)
5. Best view of the Columbia River (separates Oregon from Washington) – Beacon Rock. Short but tough climb (no gear required).
6. Most unique – Drift Creek Falls – suspension bridge overlooks beautiful waterfall. Fairly easy hike in (mostly downhill).
Thanks Larry.
besthike.com 
No Eagle Creek/Tunnel falls? I’m surprised.
I agree — Eagle Creek should easily be the #1 waterfall hike. Silver Falls #2. Ramona Falls is nice but the hike is dull until you get to the falls. Lots of good candidates for this category in lovely Oregon.
Patrick – don’t get me wrong, I love the Eagle Creek trail. There are several hikes on our website where we go there. I just felt that there were other places that others would enjoy more.
Mike – I completely agree, the hike into Ramona Falls isn’t spectacular, other than the Sandy River crossing if its a nice day. But you have to admit that the Falls itself is awesome.