It totally depends on your goals and personality but I'm going to assume you still have a competitive itch.
Though a 25minute 8K is not going to get you in the diamond league, it certainly is fast enough to win many/most local road races and get some prize money. Not Italian villa prize money, but enough to support a Starbucks habit. Joining a local running group will help the motivation, as you'll likely find other runners near your ability with which to do workouts.
The cycling and triathlon world is a bit more intense and type-A. You'll also want a good job to support this expensive habit. Again, a good community if your personality fits. Big training time commitments are required for triathlons, so that could run into conflict with the need to work to pay for the expenses!
Trail and ultra running is on the opposite side of the personality spectrum to triathlon - it really does fit the stereotype of laid back hippys who live in their trucks. I was assigned bib 420 at a recent Colorado ultra, and man did I ever get a lot of thumbs-up. And though the LR's here seem to think ultras are a graveyard for slow runners, it's surprisingly competitive. For reference, I ran the Boston Marathon injured, and finished ~2200 out of 26,000 runners. Later I ran a really well executed mountain ultra in Colorado and finished 45th out of 75 runners. Percentage wise, more of the the trail runners kicked my ass than the road runners.
I'd suggest trying everything to see what your good at, or even more importantly, what community you fit better.