Todd,
Sounds like you sail often with more than 2 people on board. The best modern replacement boat to sail with a heavy payload is the Getaway. It's about the same weight as an 18, has the wing option, the hulls are tough, and you can put a bunch of people on board with room to spare. Many sailors don't have experience with the boat, so it's hard for them to recommend it.
If you're coming from an 18, you might long for the power and trap time that the 18 is good for, but the Getaway is not slow by any means and has anoptional trap system. Will you be sailing with kids? If so, there are some good safety features built in, like a boomless sail plan, roler furling jib, and mast float. The mast is easy to raise, and it's very easy to get rigged and on the water in minimal time.
I've had one for demos around the shop since 1999 and people love it. I have sold a ton of these boats in the past 7 years to people that sail them in Santa Cruz, the SF bay and all the lakes around Norcal. Go to your local Hobie dealer and see if they can get you on a test ride to see if it might work for you.