asterisk users - May 2006 - Gigabit Ethernet with multiple VLAN's or Fast Ehternet and with two separate cards?

Hello everyone.

What's better for Asterisk: have 2 distinct 100Mb network cards in the 
system, one on the "internet" and one on the "local net" OR
have one
1000Mb network card with 2 separate VLAN's set up? It's a difficult 
decision because 2 cards are using 2 IRQ's etc but a single 1000Mb card 
might generate more PCI interrupts and get me into different kinds of 
problems.

I'm leaning towards the gigabit card because my switch supports it and 
I've seen no references to problems caused by a gigabit card + tdm400 etc.
Any ideas?

Thanks!