For you disc riders - How many races were you forced not to ride your disc?

I'm having a delemia on which wheels to buy.....

I've always been entrigued by ZIPP's. However the way they shot their prices up this year, I started thinking HED's.

I could pick up a set of:

Hed3c front and rear for 1384.22

or

HED3c/Superlight Disc for 1354.39.

or

Zipp 606 Set for 1793.18

or

Zipp 909 Set for 1864.57

(All prices include 3 Tufo S3 Lite Tires, 3 Tufo extreme tapes, Valve Extenders as needed.)

Cassettes not included.

I have a check at home in the amount of 1286.00 which have been tagged as "race wheel" money.

HED3c front and rear will cost me an additional - 98.22

Hed Disc Setup will cost me an additional - 68.39

Zipp 606 will cost me an additional - 507.18

Zipp 909 will cost me an additional - 578.57

Is it worth the extra cash to go with zipp? I'm a top of the MOP group, who average 20mph over HIM coarse. I'm racing Timberman HIM and GFT FULL this year. Lake Placid 2006.