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I'm just using MobileRSS Free version, the ads aren't intrusive, but I don't read the feeds enough to warrant actually purchasing an app.
 
I use Reeder. It syncs up with your google reader. Once I started using it it became my most used app. Downside is its $3 and the iPad version is a separate $5 app, so if you have both an iPad and iPhone that might be a downer.
 
Seconding Reeder. Probably the best $3 I've spent. It's really snappy and I can pick up on my Google Reader feeds when I'm away from my computer.

This probably belongs in another forum, btw.
 
xFeed is really nice and is free. It comes with a lot of popular feeds pre-configured, including MacRumors.
 
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