RedState has a blog on the subject today that I think sums him up fairly, and more eloquently explains the mixed feelings I have about the former Majority Leader. I think the most relevant part to me was this:
The emphasis is mine, and explains why his departure is good for conservatives, as opposed to Republicans (although it's also going to help the Republicans in '06). I don't trust people who put party above principle. It's like feminists suddenly deciding in 1998 that sexual harassment or a powerful boss taking advantage of a young girl was no big deal. It destroys their credibility as people who want to be seen as the best thing for their country, because you just get the feeling that given the choice between winning elections for their "team" and the success of the nation, they would always pick their party winning. That bothers me, even if, by and large, I would usually rather see Republicans in power.
Tom DeLay made his bones as a warrior for the party. He was, in many areas, a dedicated conservative. But he was above all else a party man - familiar as he was with the political dirty tricks during Democrat domination of the Congress, DeLay was determined not to give an inch once Republicans took power. He fought the Democrats with every tool at his disposal, with parliamentary maneuvering, with political brinksmanship, and with redistricting, just as the other side had done for decades.
I think a large part of the GOP's ridiculous spending habits can be attributed to this phenomenon. Get stuff. Bring home the bacon for constituents. Support the President at all costs, even if he's wrong. It's the letter of the law that matters.
I don't think Tom Delay was ever "corrupt" in the illegal sense. His "legal troubles" were so transparently politically motivated as to be humorous. (They probably helped him because of that.) And I am grateful that he was instrumental in wresting control of Congress away from the Democrats. But he unquestionably played down in the mud and in the back, smoky rooms. I think the Conservative Movement was better off for his presence, and is now once again better off for his resignation.