Could you recommend an app to track my whereabouts that satisfies the following:
1) I don't ride for time/racing but for exploring new areas and simply having fun with friends. Oftentimes I come up on something interesting that I want to mark on the track, be it a monument, hidden path etc. So the app needs to have this option.
2) I have some maps recorded from before. It would be nice if I could import them. Also, it would be nice if the new map has the option to export the rides to common formats at will.
3) I would very much like to be able to see multiple tracks on a single map at the same time. For example, some filter could be in place to show all tracks within a certain timeframe, based on a certain activity etc. Do you know if this exists?
4) While I ride I take photos with my camera (with GPS). Is there a way to somehow combine these photos with the track itself (I usually store the photos on G+).

Thanks a lot

Ridewithgps.com

Google My Tracks is free and will record your route. Drawing multiple tracks (especially from a query) is more complicated. I've been using MapWindow GIS (also free) for that.

I usually use My Tracks. It is just a shame Google isn't integrating it with Photos.
I could try Ridewithgps as well.

Strava will do all of this.

Nope, it doesn't have markers at least (their own reply).

here for this. i'm using strava and it's pretty awesome. i have a garmin gps watch (forerunner) but i haven't been able to pull my rides off the watch. :/ technical difficulties. i hear you can pair the garmin gps with strava but i haven't figured out how to link them yet.