SMPS - deliberations

I was looking for more info on using switching regulators for the spartan 3 when i came across a utility from national semiconductors (recently published) which gives you the right combination of regulators for a xilinx fpga; if the required op conditions are provided.

Now I am thinking more in the lines of

• 1 LM2676 for 3.3V sourcing
• 1 LM2676 for 5V sourcing
• 1 LM2671 for 1.2V
• 1 LP3878 for 2.5V
• 1 LM2676 for 1.8V (?)