It's probably too expensive for what you want, but I thought I'd just post what my plan is.

I'm on TMobile with a $65/month plan. Yeah, it's quite a bit, but with that I get 600 anytime, unlimited night/weekends, and absolutely unlimited GPRS/WAP internet access. As far as I know they're the only carrier with such an internet plan.

If the internet part appeals to you, that part is $20 a month, and I believe you can add it to any plan including cheaper ones. I use more minutes now than I used to since my mobile replaced my landline.