I wouldn't call myself an avid runner... i'm more into trail running. When I was in high school and college, I trained for cross-country skiing mostly by trail running in autumn... then rollerskis in spring/summer. I did race cross-country my first undergrad year with my university team. I have always biked, but never took the sport to a high competitive level. I do love to enroll once in a while on long mountain biking races (70km and up), one or multi-stage. I used to adventure race (now I don't have the cash, but look forward to take it over next week), so biking and running would always be present on my training. Rugby has prevented me from more intense/technical trail riding for the last 10 years of my life. But now, I moved where there is no rugby club (my body is already thanking me!), but tons of trail. The only thing missing is technical mountain biking trails that goes up 1500' and then goes down and then up, and then....
I have been commuting by bike for a looooong while, but now I am usually working in forest camps (so bike commuting is NOT an option there with 400km gravel road drives one way only), except for theses days where I am at my desk. My office is a little too far from home to do anything else but car commute: I am not ready to tackle 220km of commuting round trip every day. At least this will be over soon; going back in the woods in one month! And yeah, I will move closer (biking distance, somewhere between 0-15 mi from work) as I'll take on a full desk job in late autumn. But running has always been with me as a constant training tool. For ice canoeing also, pretty useful when you can't go out on the St-Lawrence 'cause it's one helluva snowstorm outside!
So, short story long, right now I bike 3-4 days a week, two days of technical stuff, one day of hills, the other, as I feel, could be a loooong ride mixing everyting up, and run 3 days/wk also, interval training at least once. Lots of trail riding/trail running, a bit of road riding also. Monday is off: stretching and yoga. When I'll be back in the woods, it'll be walking all day long for work, running a bit - if I feel like it, not often enough-, morning yoga, for 9 days, and then bike bike bike for my 5 day break! Three events are planned, casual racing: one mtb race of 90km, a half-marathon of trail running and a 12h solo endurance mtn bike event.