sadly, gmail/googlemail is very hostile to proper quoting practices. it hides quoted text, while leaving the whole previous message appended, without any form of > quoting. The only workable way around this is to use a imap/pop client like Thunderbird with it, which then disables a lot of the web functionality of gmail...
Just poking my head up here but how is GMail hostile? It's defaults aren't exactly friendly to lists like CentOS but I'm busy writing this in Gmail, it's not top posted, quoted correctly, doesn't break threading, is addressed to you and the list, and is plain text AFAIK. All I've done is applied the list's etiquette rules and am careful not to break them. So what are an extra mouse click or two here and there?