CLASSIC liberalism, I have no problem with, but just like modern conservatism, modern liberalism is a complete sham of its former self. Anybody who thinks there is some massive difference between the parties is delusional, or just lost in the 1980's.......
I think most people today get their info from the glen becks and whoever you want to call the crazy person at msnbc or wherever (I don't watch these programs). And this reinforces misconceptions about what each party believes and leads to a large ignorance. I think if one wants to understand about Liberalism, read Mill, Rawls, Dworkin, Nagel, Waldron, etc and if someone wants to understand about libertarianism read Nozick, Smith, Sumner, etc.
As far as conservatism goes, I don't really know where one should read. Most of the conservative books out there are propaganda and not philosophical works. I'm not saying the existing philosophical conservative books are crappy, I'm just saying very few, if any, have written on it.