Christina Warren. Erica Sadun. Two Women. Two Opinions. One love of all things Macintosh. This week, it's all about iPhone Tip Calculators. Are they a waste of Apple's time and resources, along with all those Sudoko games and Flashlights, or a clever and creative way for App developers to offer a useful product?

Tell us what you think... then read on for C vs. E in the tip-top battle royale.

Christina Warren. Erica Sadun. Two Women. Two Opinions. One love of all things Macintosh. This week, we take on iTunes rentals. Are they the next best thing or a waste of your money? We'll start the discussion and you judge the smackdown winner for the week.

Erica: Totally hot! No commitment, less than it would cost in gas, time and popcorn at the local second-run theater. Plus (bonus!) no used bubblegum under the seats. Why wait weeks for Netflix? You can watch on demand for three or four bucks with at most an hour or two of download time. Plus there's that 99-cent special each week.

Sure, I'd prefer the rental to go for 48 hours instead of 24, but it's really convenient to watch movies that I'd otherwise never get around to seeing. Rock on, iTunes Rentals.

Christina: Erica, you ignorant slut! Hey, I'm always up for new ways to watch movies, but the only real reason I can see renting from iTunes is laziness or random 3 AM rental attacks. And I haven't had random, "Ooh, I want to watch Fletch at 3 AM on a weeknight" moment since college. Weeks for Netflix? More like a couple of days -- I often get my queue replenished in 24 hours. And then I can bask in the joy of extra features, like director commentary, surround-sound, and if it's an older film, I can make sure I'm getting the latest/digitally restored print and not some digital export of a 10-year old print that was just cheap LaserDisc to DVD hack-job back in 1997.

Really though, what saddens me is how many films are available to buy, but are NOT available to rent. I can find new releases at Blockbuster, On-Demand or catch them on any of the premium movie channels, but its the catalog titles that have real potential. The Movie Store baits me by featuring Secretary on its "What We're Watching" section, but when I try to get my Spader-fest on, I find out my only option is to buy the movie. If I'm going to do that, I might as well get the DVD and watch Sex, Lies and Videotape (which is not in the store, to purchase or rent) from my own collection in the meantime.