It's certainly a bad moment for purchasing new Macs: CPU vendors will be offering redesigned CPUs in the next years with hardware fixes for Meltdown/Spectre, and you'll want a CPU with hardware fixes when they are released. If you add to that the uncertainty regarding the butterfly keyboard, as well as a slower than expected migration to USB-C (plenty of older USB ports still in brand-new accessories in the market) which makes you guess you'll depend on dongles for quite a few years to come... everything suggests that whatever Mac you purchase today, you might regret the purchase a few months from now when all these uncertainties are conveniently addressed.
I am in my second year with my MacBook Pro and I certainly don't regret the purchase. I know users of iMac in their 1st and 2nd year and they certainly don't regret their purchase either.
USB-C is something you easily can work with and the potential of Thunderbolt gives us an evolution route we never had before.
Assuming a refresh of both Macbook and MacBook Pro next week, there is no issue with the current generation of any Mac besides the Mac mini.