Flooring:
Laminate versus Wood (pro/cons)
I think that's a personal choice influenced by pets and spilled [-]beer[/-] spaghetti sauce. Bamboo wood floors have come a long way.
Wood floors may make you happier in your home, but Konecto floors make me a much happier landlord. It's perhaps a bit easier to change the décor decision with a laminate floor.
FWIW we haven't experienced any of these Konecto problems, but you'll want to ask about it before you buy:
Konecto Flooring Failure/Don't Recommend - DIY Chatroom - DIY Home Improvement Forum
Kitchen Counter Tops:
Corian vs Granite vs Marble
Good luck with sealing marble against acid attacks (see the previous spaghetti-sauce comment). Pre-sealed granite is probably available now but again I'd worry about preserving its looks over the years.
Meanwhile we love the look that Corian delivers for a much cheaper price. It's easier to match the bathroom counters with the kitchen counters. Maintenance & spills can be handled with rubbing alcohol and a green scrub pad.
I don't know about marble, but I'd say that granite vs Corian is a personal choice. You may also want to take a look at silestone.
Kitchen Sinks:
Cast Iron vs Porcelin ? Built into the countertop vs separate
I could be wrong, but all the porcelain sinks that I've encountered have been a thin layer of porcelain over cast iron. Hence the problem with porcelain sinks. There are lots of Internet web pages devoted to maintenance & repairs of chipped porcelain sinks. Worst of all is water getting under the caulk, rusting the cast iron, and causing the porcelain to spall off.
I really really prefer a large single-bowl 18-gage stainless-steel Kohler sink. Large enough to hold an entire broiler pan and the 25-pound turkey on top of it.
Undercounter sinks (especially Corian undercounter sinks) are very easy to maintain as long as you don't wonder what's growing under the overhang. (Perhaps the sink can be molded right into the countertop without the overhang.) However if you change your mind about the sink or the counter (or if only one of them gets burned or otherwise damaged) then you have to replace them both.
A stainless sink with a good caulk bead will last for years with minimal maintenance.
Tile Flooring:
Ceramic tile versus Porcelin
I'm intrigued by the porcelain concept but I have no experience.
Both types of floors are hard and cold on bare feet, and they do an outstanding job of scattering broken glass far and wide. However it's quite amusing to watch your housepets (and small kids) struggle to get a grip during turns and acceleration.
We clean our tile floors with a Scooba but spouse is perpetually searching for the optimum grout-cleaning tool. There has to be something better than an electric toothbrush and elbow grease.
See my previous comments about Konecto flooring.