I also use the Mythic tarot. I find that it tells me a bit of the past, then shows me what the future possibility is...
It also depends on how many cards you put out in the spread...
LOL Gummi Beat Tarot sounds flipping sweet. I knew a girl had a Hello Kitty Tarot deck that had the cutest death card i have ever seen.
I got a new deck for my birthday and its the Goddess deck and its wonderful. It gives me great insight.
Tarot of Pagan Cats is a really pretty deck. Being a cat person, I love the artwork! Also, the Halloween Tarot. While it is really whimsical, I think it's a great deck to read. There's a lot of depth there :)
One of the most powerful decks I have used is The Gothic Tarot, a vampire deck. Its interpretations are surprisingly up and inspiring for something with an ostensibly dark theme.
Oooooh... the Thoth deck is a toughie. If you're coming from that deck, it's going to be interesting trying to get a handle on all the Rider-Waite based decks out there (which, in my experience, makes up a majority of available decks, to some degree.)
I found the "VisionQuest" Tarot to be somewhat Thoth-like, you might enjoy that one.
As far as the RW-based decks, I have several. I love the "Cosmic Tarot" and the "Steampunk Tarot" as well as the "Shadowscapes" deck. Or try something really quirky like http://www.housewivestarot.com/
I use the pendulum sometimes as well, and sometimes I practice a version of geomancy.
OTO folks and Crowley disciples have not been universal subscribers to his deck. To put the name of Thoth to a deck promises a lot, and the Rider decks, to many, actually seem more to deliver. If you want a deck with Egyptian mojo, there are good ones like the Clive Barett deck.
Its hard to interpret at times yes and the book of Thoth can be even harder. But i found Tarot: Mirror of the Soul: Handbook for the Aleister Crowley Tarot by Gerd Zielgler helps butt tons. I will for sure check out the Steampunk tarot that sounds fun and the house wives tarot made me giggle.
I am currently drooling over some 20+ different decks, but not managing to buy a new one. I use a German myth tarot that is a bit sexist and will annoy me soon enough to make me decide.
Thoth is pretty cool. I mostly use RW just because I'm familiar with it, but my favorite deck of all time is probably the Yoshitaka Amano deck. I'm a big fan of his art, so it's perfect. Unfortunately, it's pretty spendy and not so easy to find.