I'm going out on an optimistic limb here, and predicting Democrats will only lose one risky state (SD), pick up all three easy pickups, and win four of the Republican risky states (MN, NM, TN, VA).
Here's where it will stand, the day after the election in 2008:
Democratic: DE, IL, MA, MI, MT, RI, AR, IA, LA, NJ, WV, CO, NH, OR, MN, NM, TN, VA
Republican: AL, GA, ID, KS, KY, ME, MS, NE, SC, TX, AK, NC, OK, WY, SD
Total Republican loss / Democratic gain: 6 seats.
Senate convenes January 2009 with: 55 Democrats, 2 Independents (Democratic-leaning), and 43 Republicans.