I've been wrestling with this one for much longer than I care to remember... and I'm guessing some of you too. (smiley here)

Is this the one?

Lowrance LMS-520C Sonar/GPS Chartplotter

Superb full-size 200 kHz sonar/GPS chartplotter performance that's fully loaded with pro-preferred features!

• 5'' diagonal 256-color SolarMAX™ TFT display with cold cathode screen/keypad backlighting
• Super sharp 480 x 480 pixel resolution
• 2400 watts peak-to-peak to depths of 900'
• Transom-mount 200 kHz Skimmer® transducer with built-in temp sensor
• Precision 12-channel GPS+WAAS receiver
• Built-in background map with inland lake contours
• Resize window and overlay data with choice of 4 data display sizes
• Waterproof memory card slot is compatible with a superb variety of high-detail, plug-&-play electronic chart options
• Connectivity for networking with all NMEA 200 0 protocol busses and sensors
• 5-pin ethernet expansion port compatible for radar and satellite radio
• 1000 waypoints/1000 event markers/100 routes

It might have been better not to ask. (smiley here)

I've been the whole gambit... hand helds, black and white, detail maps, seperate units, etc. and my head is still spinning. I just need to settle in on something.

I was planning on going with garmin (498c) but my partner here, and fishing buddy, John has a Garimin on his big boat and a Lowrance on the flats boat and he says the quality of the depth sounding on the Lowrance is far better.

I'm still a little out there because I'm not sure if there are additional requirements for hooking it up to the pc or transferring information but it does come with the transducer, an internal antenna or external, and I think the cards for details are only $100.

And actually I found out that unit is not available until March so I would have to go with the 332C which looks identical to me...

Sporting a full-size, sunlight-readable 256-color TFT display, the LMS-332C from Lowrance offers sonar with precision GPS+WAAS performance and high-detail mapping options at a very low price. High-speed 200 kHz Skimmer® transducer with built-in temp sensor delivers up to 60° of fish detection coverage. Advanced Signal Processing automatically fine-tunes your sonar settings, letting you spend more time fishing and less time adjusting sonar sensitivity. Includes manufacturer's one-year warranty.

While I'm at it... here's the Garmin.

Gives you the cartography you need to venture offshore! Comes ready-to-launch with pre-loaded marine map detail utilizing the new BlueChart® g2 technology. Covers U.S. coastal areas, including Alaska and Hawaii. Features include integrated mapping, 2D or 3D detail, tide and current data, improved IALA symbols, navaids, marinas, boat ramps, roads, and more. Accepts preprogrammed data cards for loading additional map coverage of inland lakes or BlueChart detail for other regions. Built-in 500-watt (RMS) sounder features Ultrascroll™ for high-speed screen updates, with the proprietary Garmin CANet™ bus enabling sounder display information to be shared with, and controlled from, another chartplotter on your boat.

Big Hook, sorry for not replying... but you could be right. I found this one that's about $200 cheaper. It's made by Lowrance but I think it's just a couple of models back but seems to do everything that I'd need.

Eagle’s FishElite 500C and 502C feature dazzling 256-color, sunlight-viewable 320V x 240H pixel TFT displays for maximum visibility and exceptional chart definition—even in bright sunlight. Sonar/chartplotter combos deliver incredible target detail and separation on a full-size 5” diagonal screen. Both units feature 12-channel, GPS+WAAS antennas, the only difference being that the 500C’s antenna is external, and the 502C's is internal.

It's over! Matt, at the South Side Boaters World, hooked me up this aftenoon. One of the most frustrating aspects of this whole thing has been the overload of information on web sites but the lack of personal expertise when talking to sales people. Matt's the exception, having used most of the systems extensively, he's a great resource if your looking for someone that can explain the specifics of each model.

4701 34th St. S
St. Petersburg, 
727.867.9700 

At any rate.. here it is: The Lowrance LMS-339C DF IGPS

An incredible new color 200 kHz sonar/chart plotter with the convenience of a built-in precision GPS+WAAS satellite antenna that's perfect for open cockpit boats--an outstanding performer that's nicely affordable.

• 5.0" diagonal 256-color SolarMAX, TFT display for maximum visibility even in direct sunlight
• 480Vx480H pixel resolution
• High-speed screen updates
• Wide viewing angles in all light conditions
• 4000 watts peak-to-peak/500 watts RMS to depths of 2500'
• 50/200 kHz Skimmer® transducer
• Temp/speed/distance readings
• FlashGraf™ LCD flasher+sonar graph mode
• Precision 12-parallel channel GPS+WAAS receiver
• All-new, built-in, background map with enhanced continental U.S. an Hawaii detail including nav aids
• One waterproof slot for digital media card (MMC/SD not included) to record graphs, GPS details, and display optional custom mapping
• NMEA 2000 compatible for networking
• 1000 waypoints/1000 event markers/100 routes