Can every gene be methylated? - (Dec/17/2010 )

Hi all,
I am new to the field of epigenetics and I am digging through a list of genes relevant to my work that I want to try a methylation study on. To reduce the size of my list I was wondering if there are any genes I can rule out as not possible (or unlikely) to be methylated. For example, does every gene have a CpG island, and if a gene doesn't, may I use this as an indicator that it won't become methylated?
I appreciate any advice you can lend!
Thanks!

hard to say as methylation is tissue specific.

look at UCSC Genome browser, there is methyl-seq and Infinium 27K array data on the hg18 freeze that can point you somewhat to what is methylated and not on a genome scale.