Apple Mac Mini (2.5GHz Core i5, Summer 2011)

Pros: Huge bump in processor speed, option for multiple HDD or SSD, choice of dedicated GPU, great connectivity options (USB, FW800, HDMI, Thunderbolt), great form factor and even easier to upgrade components yourself

Cons: No option to upgrade GPU on high end Server model. Price a bit high but still in line with previous years pricing.

Summary: First, let's get this out of the way--I can see how the absence of an optical disk drive can be an obstacle for some people but some of the reviews I'm reading are speaking like it's the end of the world. People said the same think over a decade ago when Apple was the first to ditch the floppy drive and look how much longer it stuck around. Get over it people, physical media for computing is going the way of the Dodo. It isn't needed to install software any longer and isn't even needed to recover a crashed system using Lion. If you are getting the Mini to serve as a HTPC so that you can watch DVDS, you are wasting a whole lot of money. The point of a HTPC (and/or media server) is to house your media digitally and get rid of those damn disks. And to those of you forsaking the Mini because you'd have to buy and external (a whole $50, maybe less if you go third party route), your loss.

Performance:
This new Mini is a huge leap forward from previous generations. If now has processing power comparable to Apple's other products and now even has the option for a nice dedicated graphics card. Benchmarks of the Mac Mini Server done using Geekbench have it over 9400--nearing the performance of higher end iMacs and Macbook Pros

Design:
Nothing else on the market compares--small footprint, solid aluminum case, beautifully simple.

Great connectivity options--USB, FW800, SDXC card slot, HDMI, and Thunderbolt. I'm aware that there aren't many available peripherals at the moment but most of us own a computer for more than a few months so I'm guessing it'll get some use over the next few years. And it's based on DisplayPort tech so it's backwards compatible and there are tons of DisplayPort compatible peripherals available. And unlike USB, you can daisy-chain with it.

Yes, the price if higher than similar spec'd PC models but so are all Apple products. Apple computers are premium products--terrific design using high end materials and exceptional build quality--so yes, they do command a premium price. Most importantly though, you get access to what many consider to be the primary reason for buying/using a Mac--OS X. That alone is worth the price for me.