I think it's important that at least one Godparent be a strong Catholic - someone who will be able to model and lead in a strong Catholic life. I don't think that has to necessarily be true of both Godparents (but the other ought to be someone who is leading a principled, faithful life if at all possible).
I think there is a family component to this which can muck things up. DD1's baptism was an emergency, her godparents are my aunt and uncle (who were nearby) but while they are part of her life, they aren't as active from a faith perspective as I'd like (which is odd because they're very conservative Catholics, but I think it might be normal for some from their generation?). Dh's sister is really territorial and jealous about things, she keeps track of stuff. She's not Catholic, but her husband is a confirmed (and mostly lapsed) Catholic. Dh and I talked a lot about this; as he's not Catholic either, he actually really felt like we needed to be 'fair' and ask his sister and BIL. They fit the 'rules' for baptism, and do take their Godparent status seriously so far - but frankly, I asked one of my sisters to please also take a role with dd2 just so she has that role modeling.
My Godparents were an aunt and a friend of my parents, who later left the church. I'm from a large family and saw several different 'types' of Godparents among my sisters; I do think that it's really valued and appreciated if a Godparent is actively concerned with your life - even if they live far away. It's nice to have birthday cards, gifts, etc. from your Godparents, and to have them aware of other special days (not just Church related, but accomplishments at school or whatever). I agree that helping your parents with their tasks is part of it too - I've talked with the parents of kids I godparents about spiritual challenges godchild is going through quite a bit, over the years (as well as other life issues, like lousy teachers or whatever).
When we were discussing godparents with our first two kiddos, it was difficult - our options were pretty much my sisters, and no Catholic men we could think of who were parts of our lives on any level. Old friends of mine who I wasn't in touch with anymore from college, but no one else --- Then we had a d'OH! moment a couple years ago - my roommate from freshman year of college and her husband (who was practically a roommate

) are active Catholics. Dh didn't really know them that well because they live on the other side of the country from us, but at this point, I do think that they would be who we would ask to Godparent if we were to have another child. They're from large families, and I don't want it to be a burden, but if they're willing they'd be great. Dh has gotten to know them better and really enjoys them. And they've been friends of mine for nearly 20 years now (ACK, so long!). They're here for the long haul; we don't see them very often (every five years or so) but we are in regular contact. As frequent as my contact with sisters, even!
The thing is, they would have been great for dd1 and dd2, too - we just didn't 'think' of them. Are you sure you don't have a friend who fits that profile (just one, it wouldn't have to be both)?
All that said - lacking one of my godparents, I can still say that my parents' many friends and my relatives too were good role models and concerned and active in my faith life while I was growing up.