Yep, Linux is Linux. I will differ from most here though and suggest you stick with Mint for now. You have found a great distro that you like and are comfortable with. Just learn how to use it! The grass is always greener in the other distro's yard. Instead, why not install KDE and Xfce alongside Gnome. Then you can boot into these DEs with the same install. Learn how to use all of them, it doesnt matter if you think one is "better." You want to become competent with all of them. The more you "hate" it after installing it the better reason to use it and learn it! Then, go to the WM's such as Fluxbox, then WindowMaker and e17. These three are the common ones, but there are many more.
After you are comfortable and bored with Mint then you should look around. I strongly suggest another computer if you are a real distro junkie as a live CD/DVD will never run like an installed distro. Plus, the install is a major part of the flavor. Dual/multi booting is an option, but with new computers as cheap as they are you can easily find a five year old Dell or HP at a garage sale or flea market for a few bucks. VBox and Vmware are also good options. Your resolution problem can be sorted, you just have to adjust the res in the guest.
Everyone leaves out Fedora, and maybe with good reason. But one thing I can say is Fedora will teach you Linux in a short time. It is really an awesome distro, but you have to approach it for what it is. It is a test bed for the latest technology. Not really the latest version of apps as much as experimental stuff for the Linux core. It was the first with the new xorg, it has ran pulseaudio for a year now, packagekit is now standard, it will have the most modern kernel which updates very frequently...Things like these. It also has an active community, though the forum is a bit like the wild west. You either fit in and love it or they ride you out of town on a rail. The flip side is Fedora is prone to breakage with every update, which come in at the fastest pace imaginable. It is rather like Russian Roulette. The developers are also cut off from the users. This has become a huge problem lately. All in all though, unless it changes drastically in the near future, it is a must see for the distro hopper. Be sure to hit debian also, I consider it to be the "perfect" distro in the sense it is so vanilla. What basic Linux always was and always should be. Ubuntu? I dislike it, but I greatly respect it. They are doing great things over there, and good documentation and community. But it is just so...brown...I also recommend a stage 3 Gentoo install just for the experience. Back when I started using Linux a few years ago everyone was like, "
ooh, Gentooo..." like it was some kind of Linux god. Though the general opinion is the distro is losing some of its appeal it is still a very tight OS. It has the best documentation going and is a very worthwhile experience, though you have to be a sadomachoist to use it. Likewise, Slack and Arch should be sampled.
Yeah, there are a lot of flavors in the counter, but it is all Linux. Mint is a good one, after all, who doesnt like Mint?
) so I imagine I'll revisit it once again. There are a variety of lightweight window managers like fluxbox, openbox, icewm, etc.