To parse the feeds for display on my page, I'm using LastRSS, which puts the feed into an array, and lets me avoid messing with stacks. It's a free, open-source PHP class.
I also use Abilon as an aggregator. I really like it -- it updates at intervals, and you can set it to only show you updated items from each feed. It also includes an integrated tabbed browser.
Before I found Abilon, I used RSS Reader Panel in FireFox, because I like the text balloons with the description, and I like it better than Sage, which replaced it.