All right, here's the thing: Do any of you guys know much about cellular phones? I plan to start looking for a new one over the summer, since my LG Shine has proven itself to be an unreliable hunk of dick. I selected it because it was the least shite phone at the carrier at the time, and we sort of needed to choose NOW NOW RIGHT NOW. Sine then, I have found that my list of requirements for a good cellphone has grown quite long. I don't need to hear anything about plans or contracts; I already have one and would be buying an unlocked phone if I get one at all. What I care about is the phone's form and features, and where to get one reliably.
SHIT I NEED
First and foremost (shit you not) it must be a flip/clam shell phone. I have tried bar phones, I have recently tried a slide phone with the Shine. I want to
smash them both with hammers. Preferably a fairly slim one.

The ability to reliably send and receive MMS is absolutely essential. I know most modern phones can do it, but I also know that many of them are flaky.

Not too concerned about the camera. 2mp is ideal but not required, don't need good video capture. Prefer some ability to edit photos.

Need a good web browser. I don't have a data plan
yet but I'm quite enthralled by them, and would like to have that option not suck. The Shine's? SUCKS.

Similarly, I'd appreciate a good calendar/day planner application.

Custom ringtones for my contacts. Gotta know whether I want to answer the phone before I even look at the number.

Hackability is a huuuuuge plus. I'd be thrilled to be able to hook it up to my PC and change the themes and message/key tones.

Bonus points awarded if you can recommend one with space for a strap. I fear dropping my precious.

Under 170 clams if you can help it. If you can't, eh.
I love you all and offer hideous gifs as payment to each and every recommendation, EVEN IF I HATE IT. Links are also a plus, as are recommendations for where to buy.
ALSO FEEL FREE TO JUST DISCUSS PHONES.
ETA: Herf herf, AT&T compatibility helps. I'm a smart guy.