Garmin Mobile XT.
I have "Garmin U.S. Recreational Lakes with Fishing Hot Spots".
It even list a lot of small ponds. Was quite happy with it.
I hear you can find Blue charts also.
"(Copy/Past from
HERE) BlueChart g2 Vision offers the high detail charting of BlueChart g2 plus high-resolution satellite imagery, above and below the water 3D perspective, auto guidance technology, aerial photographs for real world reference and coastal roads with points of interest."
Geeks discussion about Garmin XT
HERE.