I think Blogger also. It is owned by Google and is widely used. All my blogs there seem to enjoy good results both in PR and in the serps.
Both are about the same in terms of SEO. The very minor differences account for less than basic on-page optimization. WordPress is more customizable, so you can work past some issues, but this is at the long end of the cost/benefit scale. I'd recommend WordPress for reasons that really don't have anything to do with SEO. You can host the data yourself, there are a lot more templates available, more plug ins, too. The Akismet spam filter is pretty nice, the way categories work is pretty intuitive and still powerful - check the blog in my signture.
Yes, I agree Blogger blogs get an unfair advantage in terms of ranking in Google, But there if you have real content then seo will not be much of a problem.
I think wp is the best if u have own domain ( many plugin and many themes ) but blogger is second coz it power by google and free.
If you do not want to setup your own domain, then go for Blogger. It's from Google and you will be safe
At the end of the day, both are the same. It simply depends on how well you apply yourself. Of course for searches which involve the word blog, the blogspot blog might have a marginal advantage because of the presence of the word ''blog'' in ''blogspot''.