You would have a hard time beating a Airmar TM275LH-W driven by a Simrad S5100 and displayed on a Simrad NSS - I see they've just come out with the NSS 4 so there might be some good deals around on the very capable NSS Evo 3. The high/wide is good out to circa 150m with the Low coming into its own beyond that; you can also use the much narrower beamwidth of the Low Chirp to pinpoint fish a bit better.

Best to talk to the pro's, plenty of options to choose from at the boat show to discuss your requirements.

I brought a new simrad 15 inch ultrawide unit and 1kW transducer through Advanced Trident at the boatshow last year and saved almost $2000 from the rrp. They were great to deal with.

Botstompers recommendation is pretty much the go to for Deepwater and game fishing but if you are serious about deepdropping then stepping up to a 2kW transducer could be an option.

The TM275 HW-L is generally used by game fisherman as the High chirp has the same wide cone angle as the Low channel so good for finding bait in the upper water column with excellent definition just not the depth penetration of the low. It could also be useful in shallow water for covering a larger area finding fish. The alternative is the traditional High chirp which has a much narrower cone angle and is better for pinpointing schools of fish.

Hi, I have a 265H/l and a 175m, with Simrad Evo 3 (I swap the transducers). I would strongly recommend a Low/ Medium model. I've found fish to 350m with the medium and I find it good when trawling In fact I like it from 0 to 450m. If you combine as a L/M the low will give you wide although nowhere the detail of the high/w. I know several others who consider the low/med the best combo. Some of them are very good fishers.