I do the same thing with the same results. Usually I just find the youtube videos and play along rather than download and create audio clips, but I do have backup audio clips that I use from time to time.
I used the oldtime jam website for quite a while, but I found as I improved that the tunes just seemed to be set at too slow of a pace for my liking. I think it is great for learning and practicing new tunes though.
I agree that playing with another instrument, whether recorded or in person, really pushes me to play at the best of my ability. I find myself getting more adventurous with my bowing as well as experimenting with the notes.
We also have a weekly jam on Sundays that usually goes for about 3 hours. The great thing with that is that we play the tunes for much longer than I would normally if I was just sitting alone at home. In turn, I start finding ways to keep it interesting after about the 10th time through.
Keep us posted on how things work out with the irish tunes.