I ride in WA state too, and 3 weeks ago took a spill going about 45mph, put the bike down on the right side HARD. No skid plate. Put a hole in the clutch cover, a hole in the side of the case right above the oil overflow plug, and bent the brake pedal back. Not good....not to mention the 6 stitch cut over my right eye (yes i was wearing a helmet) and the bruises and cuts on my ribs and shoulder. Fortuneately I found parts used on ebay, but if i would have had to replace with all new parts it would have been $500+.
Needless to say I went out and spent the $$ on a skid plate. If I would have had one on I would have been able to pick up the bike, bend the brake pedal back down and ride away. As it was I walked it for MILES, with a concussion.
Its your call, but when you see oil running out the side of your case that skid plate seems like a pretty f'ing good idea.