theres many options.
most people would recommend a 5 speed swap.
theres b, d, h, and k series for options. just depends on how much you want to spend, and what suits you best.
i chose the b18b1, LS motor. im very happy with it.
some people like the ZC's. d16z6 SOHC zc, some like DOHC zc.
look around and see which engine fits your needs and budget.
http://www.jdm-online.com/welcome
that is a pretty good site to look at motors..
good luck