Actually, I have a defense of the Senate. It slows down the legislative process, with things like unlimited debate and the traditions of the Senate. Also, with its longer terms, it’s less subject to public opinion than the House, where everybody’s always up for election in less than two years. So, it can help prevent bills from being passed on the spur of the moment based on temporary popularity. (In theory, at least. As everybody knows, the Senate can be just as easily swayed as the House by something that’s photogenic and immediately popular. But, every once in a while, you get a senator who sticks his neck out on an important issue on principle. If he’s lucky, as well, his head doesn’t get cut off.)
The Senate also does protect the small states. If Congress is debating the “Let’s Nuke Wyoming Bill”, the Wyoming representative is only one out of 435, and doesn’t have much a voice. However, in the Senate, Wyoming has 1/50th of the power, and its a lot more likely that the interests of the state are heard.
The Senate also makes sure that there are people who care about the interests of the state as a whole, and not just their own district. In the House, a delegate from say, Northern Virginia, can say “I know this bill is going to hurt the people of Norfolk, but fuck the people of Norfolk. They can’t vote for me” and vote for the bill that helps his district. The Senator, on the other hand, has to pay attention to both Northern Virginia and Norfolk, and can’t “rob Peter to pay Paul”. He’s forced to take the wider view.
The fourth positive of the Senate (and, from some of the views in this thread, you might not think it’s so positive), is that it moderates extreme views. It’s usually easier for a crackpot to get elected to the House. There are fewer people he has to convince. The larger number of people who vote for a Senator, though, means that the Senator’s views are going to be more in line with that of the country as a whole. Also, with the larger pool of voters, election fraud and fixing races is harder, and the Senator is less indebted to activist and special interest groups.