I hope I don't sound like a Mac Fanboy, because I've certainly looked at the PC market. But by the time I got done comparing comparable platforms it was all a basically a wash. Plus, like you, I was already heavily invested in the Mac software.
I do love my Macs though, but that's probably because I know how to keep them clean.
BTW - I have heard that Lion sucks.
OS X Lion does suck. I've used Mac laptops exclusively for 7 years now and they have consistently become worse, first with the intel CPU's and now OS X just losing steam. I reinstall every 6 months at least (like you had to with windows XP), reboot or force reboot several times a week. In the old days of the power pc my uptime was 45 days + on average, now?
7:44 up 5 days, 15:01, 2 users, load averages: 1.16 1.60 1.79
. Too weak for such an expensive machine.
It's not a particularly good machine for editing, IMO, the memory management seems completely screwed, on my 2010 MBP 15" i7 2.66 ghz 8gb ram anti glare hi res machine I can bring it to a complete halt using photoshop and LR at the same time, as soon as I starte building files with more than 5 or 6 layers it gets these hiccups and will freeze for a while, I suspect that it is os x moving files from RAM to HD or the other way around, I could probably cure it with an SSD but I like inexpensive drives that I can change once or twice a year. This problem has gotten a LOT worse since lion. It was hardly noticable on Snow. The screen is ok but low res 1680 x 1050, I love the design of it and that it doesn't really make any noise and that it is quite slim and nice to look at, i love the keyboard and the trackpad and I love when I open it op how well organized and beautiful the black circuit board and everything is inside of it, but as a production machine? Nope, not really, it's just a turd in a pretty frock.
I don't know what the alternative should be, but OP should get something with a better screen, ESATA?, There aren't enough I/O-options either in the macs, IMO, I want esata, USB 3, Firewire and Thunderbolt at the same time and more ports.
I have two stinking usb-ports, thunderbolt, firewire, that is it, they took the nice eSATA option away with the express port they somehow managed to exchange for a SD-card reader that doesn't work. What the hell.
I have a dektop machine too, it has 6GB of ram (but better and faster ram than the mac), two graphics cards in sli, 1TB storage in RAID 0, external 2TB storage in RAID 1, 3.3 GHZ i7, two firewire ports, 14 usb ports (2 are usb 3.0 enabled, four are eSATA enabled) that cost a lost less than half of what the Laptop did. It's older but miles better.
I've always fancied the Dell Studio 17, don't know if they are any good.
I took the liberty of making these two, the Dell has been top specced, every option chosen as "the best/most expensive", crap like software, anti virus, cables and mice I have not chosen. You decide. Dell XPS 17
Nvidia 555M 3GB
17.3" 1920x1080 display
Dell Ultrasharp 24" widescreen
i7 2860QM 2.5 ghz
Macbook Pro 17"
1920 x 1200 hi res low glow display
Apple Thunderbolt 27" display
i7 2.5 ghz