'08 Garmin g2 Blue Chart worth it as update to preloaded '06 g2 in my GPSMap 498?

[fendertweed]

I have a 2+ year old GPS Map 498 Sounder in my Pearson 26, with the built in map, Garmin g2 2.00.

In late September I'm going to take my first cruise down the Potomac ~80 miles from Mason Neck & back and wonder whether the newest G2 Blue Chart datacard will be significantly more useful/better.... having photos etc. of the various marinas & inlets/rivers/creeks I'll be using for docking & anchoring would be a plus, to be sure. I'll be taking a week to make the trip, approx. 170-200 miles round trip probably.

Any thoughts on the update g2 Blue Chart map?

Thanks,
Jon