Does this accurately describe your reaction to John McCain? If it is, I quite agree.
In fact, I have no intention of supporting him whatsoever. I've been holding my nose for the Republican presidential candidates since I was old enough to vote, and I haven't seen much of a return on my support. Up to now, they've been lackluster at best. This year, the Republicans managed to nominate the only human being that could make me look back on either of the Bushes or Bob Dole and say "I wish our nominee was one of them instead".
Now, everyone is adamant that we vote for McCain. They say there's a world of difference between him and Obama, and let's say that's true. What's he done about it since 2000 or so? When was the last time you saw McCain oppose a Democrat or their agenda points in any way before he started running for President? In fact, what else has he done but join with Democrats, poke his fingers in conservative eyes to build his fake maverick credentials, and revel in the puff press at our expense?
Can you say for certain he'll support or ignore any of those differences at any given time, knowing his obsession for media accolades? His love for their attentions is the only thing about him that's predictable. How is he going to react when he's President, and that very same media is around him all the time, waiting to hammer him for his departures from their orthodoxy, or glorify his breaks from his own party?
If you see him becoming even more of a donkey in elephant's clothing because of this, I do too. Not only that, but his entire party will fall into line behind him, just like they did under Bush, and walk right off a cliff yet again. It kind of takes the edge off the argument that he's an improvement over Obama, and demoralizing to boot.
So what am I going to do about this? I'm voting my principles with a third party instead this year. Personally, I like Bob Barr, but for those of you who aren't of the Libertarian bent might want to look at Chuck Baldwin of the Constitution Party instead. Do they have a real chance of winning? Historically speaking, no. Does that make it a wasted vote? Look at the other choices, and make your own decision. You already know mine.
I find this preferable to sitting out the election, and here's why you should think twice if you're considering doing that yourself. Yes, I agree with you that swallowing the jagged horsepill of the McCain candidacy is asking too much, but his undeserved nomination isn't the only issue here. There's the Congress to consider, because it's the source, or obstruction, of the real and long-term damage.
Why care about the Congress now? Surprisingly enough, the congressional Republicans have started taking desirable action, especially with regards to energy policy. While you may not give them much thought in a presidential election year, this time you really should. If you decide to stay home, you could be costing a decent representative or Senator their job a la Rick Santorum's undeserved fate. I have one such deserving Senator on my local ballot this year, and I'm definitely voting for him regardless of McCain.
Therefore, even if your reaction to McCain is 'yeah, right' just like mine, don't stay home in November. Look into a third party candidate so you have someone to support. A third party means you can vote your principles for President, send a message to the RINOs that they can't take you for granted, and not sacrifice a worthwhile conservative representative or Senator to do it. By all means, let McCain take his own electoral thrashing, but leave those who don't deserve one out of it.