Choosing a SPICE model

I'm bewildered by all the different versions of SPICE.

I run on a Mac, but I have Parallels available. I've also heard that I can use Crossover or WINE. I'm hoping for something easy to use, analog and digital, capture/analyze/waveforms, and low or no cost. And, I need a reasonable parts library.

So, what do people recommend? PSpice (student version 9.1)? LTSpice? MI-Sugar? Something else?

Thanks
Eric

They are all derived off the same public-domain Berkley code. LTSpice is by far the best, and it is free.

he guys can we use LTspice for proteus