I've been dual-booting Linux and Win7 for the past 4-5 months.
Tried dabbling in it back when it was Jaunty Jackelope (forget the exact number). What happened back then that put me off was that every time I ran the updates, it wouldn't boot after that. I know now (after having experienced it multiple times and looking it up to fix it) that it was the problem with updating the Kernel causes Nvidia & AMD drivers to freak out. So that ended it for me for a while.
Started out recently on Xubuntu-x86 10.10, set it up with an OS partition for Windows, OS partition for Xubuntu and the extended partition for media files. Spent a long time transferring files from the ntfs partition over to the ext4, reduce the size of the ntfs, expand the ext4, repeat multiple times. Then I had to go and fubar the whole thing when Gparted live moved my entire Win7 partition over by 5 mb. Many bad decisions later and I decided to reformat the whole HDD (all of this is from a laptop so only 1 drive), amazingly I was still able to recover anything that was on the ext4 partitions... ntfs? Not so much.
Went with Kubuntu-64 10.10 and liked it for a while, then I hit a bunch of bugs with it, sure it would crash sometimes or freeze for a few minutes, but I didn't immediately run away back to Win7. Just work through everything, search forums, search google, almost all my problems had been experienced before and were well documented. Mixed up problems with a language, all my menus were in Japanese, tried something wrong and found that my environment file was wiped out, so all the basic commands in Terminal were gone, hell even "ls" and "sudo" didn't work. Unfortunately, I also ran into the Kernel update problem again (this was/is the last time I swear!) so here I was, I could fix the environment file with a gui and to fix the gui I needed to use a CLI to reset Xorg. Headaches ensued for a while.
Eventually got tired of the bugs with KDE and switched to Gnome. Works really well, now I am running 11.04 Natty Narwhal Beta and I am liking it. Unity is not as bad as everyone is making it out to be, sure the buttons are larger and tablet optimized, but all the important apps I use all the time I have the Terminal commands memorized.
I still have to use Win7 mainly for programming in LabView and some gaming (too much school, so little time). A major point that people bring up is all the extra time spent looking up fixes. People here spend a ton of time perfecting their overclock and sometimes for a simple 5 minute benchmark. I am not hating on overclocking but, a 20 minute search on Google for a problem solved permanently is perfectly fine with me.
Linux is a great way to learn what is really going on in an OS and is rapidly evolving faster than any large corporation can hope to keep up with. Now true Microsoft and Apple have tons of money to throw at R&D, but in reality how often do they really listen to the consumer? Yes, they might accept your input but ultimately they will do what is best for them and their profits. Linux gives the developers and the users to get exactly what they want. If they make a bad decision and it is received poorly, they don't lose profit. People might move away from them for a bit but that just forces them to redouble their efforts and make something incredible. I heard it before on the thread. The true joy of Linux is the choice that the user has. Since Linux for the large majority of people is free, you do not feel bound to any one flavor of Linux. You won't lose any money from hopping back and forth across the different distros.
tl;dr I ran into a lot of problems initially with Linux, about 95% of them were my own mistakes and I learned a lot from it and I absolutely love Linux. Having said that, I also understand the uses of Windows and the use of it for niche programs (Photoshop or LabView or Gaming). As it stands right now I can't completely cut myself off from either one of the OSes. From my perspective, Linux has the flexibility to change with the times and adapt to best fit the people's needs and wants. Windows will be the industry standard for many years to come. Neither are utterly useless and neither can completely fulfill every role of the other OS.
Next, I'll start delving into the other distros and really see what is out there.