i moved from sacramento to seattle a couple years ago. seattle's awesome and all, but for riding, it's not the best place in the world (not if 95% of your riding was at the delta and/or sac river). if you like riding the sac river, there's something similar to it about 3 hours east of seattle, but the water's freakin' cold!
lake washington's good...in the winter, where air temps can be in the 30s to the 50s and water temps in the low to mid 40s.
lake sammamish is good in the morning (butt crack of dawn) and in the winter (temps same as above).
lake meridian, is small, but it's good during the week.
if you're like me and need smooth water to ride, your only options could be early morning riding during the season, winter riding, or making trips out east.