clustering RNASeq data

[PFS]

Hi,
I would like to do some lustering of rnaseq data.
I used tophat/cuffdiff to get a table with the fpmk values.
Beside the quantile normalization option in cuffdiff, what other trick has to be used with this type of data before clustering?

I read on EdgeR manual about the particular choice of distance. I was thinking of using correlation as distance. Is that not appropriate?

Thanks!