Multiple Plugins For SEO Dilemma

I have got a plugin for SEO (All In One SEO Pack-standard version) and Add Meta Tags-standard version. I would think that this would present a conflict, although, so far the work that they perform appears to be good.
1.) To do an effective SEO, can these work in tandem or should I drop the Add Meta Tags.
2.) If there is a plugin that you find superior to the above plugins, that being accomplishing the above, I would really value your input.

Thanks, b