Hi Mega,
My DH and I just recently went through the same dilemma! We live in East Lakview and we were on several waiting lists while I was pregnant. My DS was born in December and I returned to work in early March. As no spots were open at the various centers, we had to go the nanny route. We put a post on craigslist and did a nanny share two days per week at another family's house (they had a 15 month old boy). The other 3 days I had a friend (also a nanny) look after him. The nannyshare worked really really well. We just finished this arrangement as we have been offered a FT spot at Concordia Avondale center.
If it was in our budget we would loved to have done the nannyshare on a FT schedule as it was really convenient for us (the other family lived 3 blocks from us), the nanny was very reliable, never late or off sick etc. and our DS received lots on 1-1 attention. Now that he is going to daycare, we are excited as he will be able to socialize with more kids but by the same token probably get sick more often!!
If you decide to go the nanny route, craigslist is a great source, as is Northside Parent's Network...
Good luck!
A.