It usually depends on the page rank and inbound links of the site. You never know which link Googlebot would ride on to get to your desired site. So, the higher the page rank, the higher the possibility and the lower the turnaround time to get indexed. Some high rank sites get Googlebot attacks many times a day. I have experienced this with Xanga blogs. But, if you have a sitemap installed in your website, then it should not take more than 24 hours.
Lately indexing is pretty fast, but in general it can take from one day to 2 weeks. I think reindexing of expired domains takes more time than a fresh one, but this mayby just my superstition.