Personally, if I were going to do it today, I'd be taking a serious look at Garmin's new stuff, where, with a single, configurable display you can have depth, speed though water, all your wind data (real and apparent speed and direction), water temp, air temp, barometric pressure (I believe). Will integrate cleanly with your GPS and I believe will display (some?) GPS data.
We currently have ST60+ knot meter and depth sounder. They work well and we're happy with them.
The problem I have with the integral units you describe is that if something goes wrong with just one display unit then you lose depth, speed though water, all your wind data (real and apparent speed and direction), water temp, air temp, barometric pressure.
And also, every time one wants a different bit of information, you have to start pushing buttons. Unless it's all on screen at the same time in which case it's a pretty large screen or pretty small characters.
I have recently installed ST60 wind, speed and depth and so far I'm happy with it too but it's early days for me. In all honesty, I went for the ST60 stuff because I already had their autopilot and the whole instrument setup integrates with the AP.
And it just seemed so uncomplicated to simply connect up the Seatalk cables.
And they will integrate with my GPS.
And they were on special.
And everything is one integrated system.
But I'm still relatively safe from a catastrophic failure
And BillyR, while the wind stuff is not a threat to safety, it's pretty indispensable for me when sailing at night.