I need to run about 40 Ft of cable to my surround speakers. Is that going to cause any delay problems?

Absolutely not - in fact, 40 feet is a pretty common length. Keep in mind that the speed that the signals travel through the speaker wire at is a lot faster than the speed of sound.

The length of a speaker cable run does not impact delay. What is important is that the cable be sized appropriately for the power anticipated at the speaker and for the length of the run. The longer the run the greater the diameter the wire needs to be. For a 40 foot speaker cable I'd recommend at least 14 gauge speaker wire or 12 gauge (gauge is inverse of wire diameter) if your speaker terminals can handle that size. While there is much debate over the effect of wires on the sound of the speaker IMO a good quality wire of the appropriate gauge is more than sufficient. In my case, I'm using 14ga in-wall wire from Cables To Go with maximum runs to my surrounds of about 30 feet. I have 4ohm speakers and a 300w/channel amp and the speakers sound fine.

Alright, so where is the cheapest place to pick up some white 12 gauge?

If you're wanting to pick some up locally, Home Depot carries some pretty inexpensive stuff, but I don't know if they have white or not. Radio Shack might be another option for you.

I bought 12 ga in 100' spools from Totalsignal.com . Same wire as from rat-shack.
A lot less expensive. Very happy with it, the shipping, service, quality. Sounds great. Not white. It's not listed on his website, so you would have to send an email linked from his contact us page.

He also has other cables

You can get 100 feet of 12ga in-wall wire with a white jacket for $80 from CablestoGo.com. The white jacket has printing on it (to identify it) unfortunately I was not able to remove the printing with acetone or mineral spirits. If the you don't mind the printing it is good cable. They have 250 and 500 spools too.

If you need white, AvFan has a source.
I think my clear 12 ga (see above) cost me $30 or maybe $35 with shipping...but nowhere near $85

AvFan's source is also in-wall (presumably rated for in-wall or plenum installation), which can add some cost. If you are running exposed (as I did at my old house), you don't need wire that's rated for in-wall use.

The insulation should have CL stamped on it for in wall installation. Jim