On the Macs, I’d suggest waiting a couple of weeks until Steve Jobs delivers the keynote address at Apple’s World Wide Developers’ Conference on Monday, June 9th at 10:00 a.m. PDT. It’s possible that new MacBooks will be announced, and perhaps a new Mac mini in a smaller case.
Most people don’t need professional quality image reproduction, but if you do, I’d recommend the Mac Pro and a Cinema Display. The 24-inch iMac is also a good choice if you prefer the glossy screen instead of a matte finish. Note that the 20-inch iMac uses six-bits per color channel on the screen, but the 24-inch uses 8-bit channels.
For digitizing broadcast video on Macs, check the products at http://www.ElGato.com
For MS Office-compatible applications on Mac, see Apple’s iWork suite. It costs about $80. A 30-day trial package is included on new Macs, so you can try it before purchase. http://www.apple.com/iwork/
If it's a MS Office compatible apps suite you want, why not...MS Office?