Well, as a Greek, I'm all in for beaches. Summer here is like a sacred thing, we patiently wait for these 3 months of the year and choose our summer vacation from our hundreds of islands. :)

A bit of both can recall going up in some of the mountain areas as a child with my dad in both Wales and up in Scotland. As for beaches, seeing that most of my family came from Cornwall, the coastline is lovely as well as many of the beaches. In all weathers too! 

I favor the beach any day, but as I've gotten older some nostalgia has crept into my time in the mountains.  I just get so motion sick, so mountain roads are my nemesis.  

My favorite beaches are the ones in Central California. 

I prefer the beaches in the mountains.   Lake beaches can be and sometimes are more relaxing and more fun than the ocean beaches.

Anywhere there are not a lot of people will do

When i was a.kid i used to visit a beach on tbe New Hampshire coast. I would like to pay that beach a visit again sometime.

Hampton Beach

Nothing beats a beach especially a Caribbean one.  Bluegreen waters and white sands.  That's me all day.

Nantucket Beach is an awesome place..

Beach

Yes?
Both is best, mountain lakes are fun to swim in, and there are always little secluded spots for a little...fun

Mountains all the time. 

i prefer bitches

Many good points. Probably needs more people to read through this.

I live close to mountains and i love it. Plenty fishing and hunting

The beaches in SEA are the best.

Big fan of mountains here. There are a lot of very nice places not too far from home ;)

Mountains! Skiing and then the apres-ski beaches just burn me haha