Krzysztof Cyran and Marek Kimmel (2010) have presented a revised set of estimates of the human mtDNA most recent common ancestor (MRCA). It's an interesting theoretical paper, written for the purpose of developing a method that doesn't rely on the same assumptions as the usual coalescent models.
Their new method gives an estimate of 174,000 years ago for the human MRCA. They report an upper/lower range as 96,000 to 449,000 years ago. That range does not represent a confidence interval on the estimate, it's an upper/lower based on extreme assumptions about human/Neandertal genetic distance and the human/Neandertal MRCA.
The Neandertal mtDNA has really affected the way we estimate human MRCA, at least for the mitochondrial genome. Chimpanzees are just too distant. When we compare human and chimpanzee mtDNA genomes, there has been a lot of parallelism and reversal on both lineages, because mutations have hit the same place multiple times. Multiple hits and purifying selection make a mess out of rate estimation -- generally, they make the human MRCA seem a lot older than it truly was. The Neandertals are closer, and are therefore less of a problem.
But the Neandertal-human MRCA itself was poorly known, as long when we had only chimpanzees to calibrate the mutation rate....