It is kind of weird, since Apple pricing stays fairly static (the 13" Pro threw a slight wrench into the works) and if anything has gone down over the years (When I got my MacBook back in '06, the MBP 15 was $2000 base, it is now $1800 base I think), but the specs change. And there are times, usually right at the time of refresh where they are the best deal on the block, and sometimes the only place to get something. They were the first with the 8600m and Santa Rosa I think, and held that for a couple of months.
There are also lots of little features:
1: Glass trackpad (and before the ignorant can say anything, it does click, the whole thing is hinged at the top, and you can flip a software setting that allows the bottom right click to be a right click) with multi-touch. The, hands down, best trackpad in the industry. It is spacious, will basically never wear down or get shiny, feels great to use, is sensitive and responsive, is automatically disabled when you start to type and is just amazing to use (especially when compared to any other trackpad out there)
2: Long battery life without extra battery packs, and with a full powered system. Regardless of whether you think they could have crammed a Core i7 Quad into the MBP 13, the fact is that the Core 2 Duo that is in there is still faster and better than the ULV chips in other laptops with 10 hour batteries.
3: Backlit keyboards on the Pro lines.
4: MagSafe connector.
5: Sudden Motion Sensors in all the laptops.
6: Ability to dual boot anything, legally.
7: The VM software on OS X is incredible. They are easy to use, good looking, fast, stable, and are pushing what they can do (3D graphics, gaming support, use your bootcamp partition as a VM so you don't have to waste HDD space, or reboot to make changes)
8: Apple retail presence. They have a store in almost every state, often more than one. If something goes wrong, you can take it to an actual human to have it be diagnosed. They can either fix it there, or send it out from there, and it can either be shipped to you or you can pick it up from there.
Are they more expensive than their PC counterparts? Most of the time yes.
Is it by a lot? If you happen to want everything that the Mac has namely, WirelessN, Gigabit LAN (not all laptops have this yet, but almost), BT, backlit keyboard and whatnot then usually not by much, and sometimes are darn near on parity. If you can get by with fewer features, then you can save a lot going with a PC.
Is it the only legit way to run OS X? Yes. So if you want that, then you should buy a Mac.