Matlab: What do I need for modeling?

I'm not intimately familiar with Matlab, and I'd like to know which pieces I
need for a project.  Normally I get filter coefficients from ScopeFIR, and
then go straight to Verilog.  Sometimes I model FIR filters, mixers, etc.,
using behavioral Verilog, but more often than not I just go straight to the
synthesizable Verilog.  I can simulate this in Modelsim and do a DFT on the
results using ScopeDSP.  Then I can change bitwidths or filter lengths based
on the results.

What if I need to make a Matlab model before making synthesizable code?  It
seems to me that making a behavioral Verilog model is just faster and easier
to use as a base for synthesizable code, but I haven't used Matlab in a
while so perhaps I'm mistaken.  Do you know which of the many toolboxes and
add-ons I'd need to do this?  I just want to make a simple fixed-point model
of the DSP chain, including FIR filters and mixers.  Can I do this with just
the basic Matlab package?  I don't even need Matlab to generate the
coefficients or to make pretty block diagrams or plots.

-Kevin