If you read one speech by Reagan, make it two. The speech after the Challenger, and the speech where he dared Gorbachev to "tear down this wall."
UPDATE: beware the GOP attempts at revisionist history. Much of Reagan's success as President owed to some of his decidely non-conservative policies:
Reagan is, to be sure, one of the most conservative presidents in U.S. history and will certainly be remembered as such. His record on the environment, defense, and economic policy is very much in line with its portrayal. But he entered office as an ideologue who promised a conservative revolution, vowing to slash the size of government, radically scale back entitlements, and deploy the powers of the presidency in pursuit of socially and culturally conservative goals. That he essentially failed in this mission hasn't stopped partisan biographers from pretending otherwise. (Noonan writes of his 1980 campaign pledges: "Done, done, done, done, done, done, and done. Every bit of it.")
A sober review of Reagan's presidency doesn't yield the seamlessly conservative record being peddled today. Federal government expanded on his watch. The conservative desire to outlaw abortion was never seriously pursued. Reagan broke with the hardliners in his administration and compromised with the Soviets on arms control. His assault on entitlements never materialized; instead he saved Social Security in 1983. And he repeatedly ignored the fundamental conservative dogma that taxes should never be raised.
All of this has been airbrushed from the new literature of Reagan.
UPDATE: an excellent point which is also in danger of being papered over by modern GOP revisionists as an inconvenient fact, even though it is actually critical and profound:
So tonight, as we live in a world where the danger of nuclear war is much lower than it was in 1985, when Reagan and Gorbachev first met, let us praise Reagan for ignoring the advice of those who said bargaining with Gorbachev would endanger the safety of the free world, especially then-Defense Department official Richard Perle and then-Wyoming Congressman Dick Cheney.
UPDATE: Kerry's statement on the death of Ronald Reagan. It's a noble gesture of respect which all Democrats would be wise to heed.