I'm currently tracking all my finances with GNUCash, and splitting the various paycheck deductions into expenses. It's pretty nice to be able to correctly predict what will be on my W2, and it's even better to be able to calculate net worth.
But I'm unsure of how to account for future social security benefits. I'm currently just marking the deductions as expenses, but this is understating the present value of (distant) future income. Any ideas on valuing SS as an (illiquid) asset?