I could do without Beck, but he's not prime time. (He competes with Oprah in terms of time slot.)
O'Reilly's show is completely different from Countdown. You can't find a single similarity between the two. O'Reilly is funny, likable, professional, and rarely looses his temper. His show is diverse with a lot of funny segments that have nothing to do with politics. It's a great show, there are a lot of reasons why it gets top ratings.
I've been watching a little bit of Parker / Spitzer lately, it's not bad. Spitzer's a bit a loud mouth but he makes for a pretty darn good co host.
MSNBC needs to compete with these two shows, they need people who are opinionated and intelligent, and also likeable. That's the quality both Olberman and Maddow lack currently. I don't think Olberman can change that but I think Maddow could if she wanted to. She really is quite smart, she just needs to "grow up" a bit.