Yes weight really matters.
But if your like me this would help, im 6' 3" 180-185lbs and I ride a 42 inch.
If your less weight i would say 41.75 - 42. If your much heavier then shoot for around 43 inch.
The dimensions are the most important but when it comes to a board maker that are a lot of great ones. Most top models are going to be good enough and it comes down to the rider but I know bz, Morey, Nmd, science, found etc are all great. For all around riding go with polypro.
Im a big fan of churchill fins and stealth, I go into a ridiculous amount on this little topic on my site
www.churchillfinsreview.com I would recommend any fin on there and with other fins i review that arnt good I say in the review if they suck : )