I'm a bit (very) biased, in that I consider giving money to Microsoft a horrible sin. Sony has plenty of faults, but they don't approach the evil of Microsoft. So take my opinion with several grains of salt.
I've got two gaming systems: a high end PC (running funtoo linux, using Wine to run those games I have that don't run natively on linux) and a PS3. My time gaming has been split pretty evenly, for a while, but I usually end up only playing a few hours a week. This is partly because I'm working two jobs (I'm the tech department for a K-12 school district and a linux database admin for a company called Consistent State), roughly 60 hours per week, but it's also partly because I've been spending more time playing with things like server setups and the like than video games. Still, I have an opinion, and I'm going to state it.
For me, the dualshock controllers have always been very comfortable (I have very long fingers, so "ergonomic"-style things don't fit in my hands). The argument about 360 pads vs. PS3 pads seems to be kinda like the argument of Logitech gaming mice vs. Razer gaming mice. Logitech designs their mice for average to large size hands, so that people with average to large size hands can actually rest their hands on Logitech mice. Anyone with a particularly small hand or extremely long fingers, however, will find the Logitech horribly uncomfortable because they have to hold it in a strange way. Razer's mice are not really designed to rest your hand on - they are designed to be held on the sides, and have very large, flat buttons to accomodate different finger lengths. This works better overall, but for the group whom Logitech's mice are designed for, Logitech mice will feel better than Razer mice.
Sony's gamepad is not meant to be gripped, it's meant to be held loosely. Which is something I like, because my fingers are too long to allow me to grip any gamepad; the excess weight and the "ergonomic" shape of the 360 controller kind of cut into my fingers because the joints of my fingers don't rest where Microsoft meant them to. Sony's pad doesn't really have any "ergonomic" curves, so it's not really designed for finger joints to rest in specific places - it works better overall, but for the average size hand, the 360 pad will likely feel better.
For the rest of your decision, well, the PS3 is technologically superior, but it's also very weird. The CPU structure on the PS3 involves a dual core RISC-based CPU as primary, then seven (I think) secondary vector processors. In layman's terms, the vector processors on the PS3 are designed to be most efficient when running operations on vectors (arrays) of values. This is where the PS3's power comes from, but it means absolutely _nothing_ if companies don't figure out how to program for it. To program efficiently for the PS3, you have to think "Alright, now, I have to do this expensive operation to this variable ... are there any other variables that will need this operation done in the future that I can add to a vector so that I can free up a few hundred CPU cycles? Or was the operation done on something else, earlier, so that I can add this value to that vector?" This is why multiplatform titles tend to suffer on the PS3 - the companies don't want to bother with special programming for the PS3, so they just decrease resolution, disable features, etc, until the same code that runs on the triple core 360 CPU will run on the dual core primary CPU on the PS3. On the other hand, companies like Naughty Dog (Uncharted, Uncharted 2) have been building libraries for other companies to use when programming for the PS3, so multiplatform support has gradually been getting better.
The 360 is simpler, using a much more standard triple core RISC-based CPU (I think I'm right about that - it's been a while since I got involved in this stuff), so nobody needs to study special programming for a different style CPU. Multiplatform games will usually turn out better, here, but exclusives will look roughly the same as the multiplatform titles.
Finally, and this is only important if you're a real geek, if you pick up an earlier model of the PS3, you can install linux on it. It's not the fastest computer in the world, but it's _very_ good at certain tasks and allows you to rip bluray disks to a hard drive (in other words, you can save those 1080p bluray movies you've got to your computer). Plus, if you're a programmer, it allows you to play around with programming for the cell processor - something I had a lot of fun with.
I prefer the PS3 mostly just because I love weird technology, and messing with the vector processors in linux is a great deal of fun. The free online play is also nice (there is no way in Hell I'd pay for online play, ever), some of the games are simply awesome (I have a lot of fun with Warhawk and Metal Gear Online), and the PS3 gamepad, while annoying to some, is a whole lot more comfortable than the 360 pad, to me. It seems to have great reliability (I've had a couple of games freeze on me, around the time firmware 2.1 was just out, but no problems since) and I haven't run into many people in online games who are complete morons (that may be due to the games I play, though).
So yep. There's my opinion. In novel form.