A G O N Y

really gives you a feel that there was a diverse landscape there very long ago. oceans, lakes, rivers

Actually not many if any of the formations there constitute a lake =) And maybe possibly a riverbed in the far left of the image. Just cause its blue downt mean water= )

upon closer exam its possible some very small riverbeds exsisted, however there is a likely chance they are just windcarved channels.

Well there is the whole mars rovers found a lot of evidence that standing water existed on Mars. Based mainly on the massive amounts of minerals that form in water that were found.

Yup but not based off landscape features =)

Well, isn't there an icecap or something on the planet? That in itself suggests water /smack forehead

Yeah but icecaps can be formed from a number of events. Icecaps ussually come before formation of large water bodies. IE they melt to make oceans =)