Help me choose a GPS for my boat

[biggdave92]

I have a 76CX but i want a GPS that will stay mounted in my boat.  I would like a unit with a big screen.  Prefer color.  I basically want a 76CX with a big screen on a permanent mount on my boat.  I have looked at the Garmin website and it looks like the 531 is about what i'm looking for.  Is there an older model that i need to check out.  I'd like to keep the cost under 300.00.  Love the site!  Thanks!

[atbspinner]

Check out Overton's.  They have several units in the $400 range with $200 rebates available. 
I'm looking for a handheld unit for lake use.  How does the 76CX work for you?  I know the detail
is limited on that size screen.  I'm trying to get around a lake with 900+ miles of shoreline.  Thanks.