MFP thinks if I eat like today I will gain 1lb every month!

So the obvious response here is "don't eat like that every day if you are trying not to gain weight",

This is a calorie counting website. That's how it works.

My "goal" assumes weight loss.

But MFP thinks it is my maintenance? Why?

Well, first of all, you are actually at maintenance now...with three pounds left to lose. 1700 sounds like maintenance if you are Sedentary, and don't exercise.

Well, I am going to go against what everyone has posted. I am 5'4", 137 pounds, and I can eat 1700 calories without gaining. That is not to say everyone can, but MFP tends to set things on the low side. Unless you are entirely sedentary, old, or have some type of metabolic disorder, chances are you will lose on 1700 calories (or at least maintain).

Same here. 5'0", 112 lbs and I eat between 1800 and 2000 calories a day (with a workout at least 5 days a week). I recently had gone up to 118 (eating way more than 2000 and not logging) and was able to get back down to 112 in 6 weeks eating 1600-1700 a day. MFP does indeed underestimate in a lot of cases. You can manually set your goal if you prefer and ignore that silly "5 week" message.

I'm 35. I am fairly active. Most weeks I strength train with a personal trainer twice a week and run 3 times a week (5K minimum run, 10K max). BUT, I eat back every single exercise calorie. That's a rule I have for myself.

For the last month and a half I only lost 1.5lb, but that can be attributed to a 17 day vacation in New Orleans and SF (eating out 3 times a day, and having drinks, so most of them cheat days), and a birthday weekend.

As for the thought that I am in maintenance because I only have 3lb to lose... That's an number I arbitrary set.
I could have set the number to 110lb, like I've seen some people do. Than I would be considered not at maintenance, while at the same number of calories?

MFP is a "dumb" tool. It takes what you input and runs an algorithm and then gives you an output. It sounds like you've used another site to calculate your calorie goals (such as scooby or something similar), meet your goals, but then when you close your diary, it tells you something stupid. Likely, it is guessing low AND you might not be logging exercise or have your activity set right (if you're doing TDEE method, you're not supposed to log exercise or log it as 1 calorie).

My suggestion is either stop closing your diary or ignore what it tells you. And if you are using MFP to calculate your goals, make sure you are logging both food and exercise accurately, you have the settings properly set, and you try to meet your intake goals.

What's the TDEE method? I've seen people that log their exercise as "1" but didn't understand why. I manually set all of my percentages based on what my trainer and nutritionist have recommended and stick to that and the log my exercise at the end of the day. I see that by entering your exercise it does "up" your daily allowances and that I'm assuming is detrimental to weight loss???

This website is set up to calculate based on your stats and how much you want to lose how much you should be eating. It takes into account your activity level, age, weight, etc. How much it tells you to eat has a deficit calculated to give you the amount of weight loss you say you want each week. If you said you were sedentary on your activity level but then you decide to do some exercise, you need to log your exercise with an accurate guess of how many calories you burned. You then eat those back because MFP already gives you a deficit.

Some people don't like eating different amounts every day. They use other calculators or tools to help them figure out how many calories they burn on average each day over the course of a week. That is how many calories they would need to maintain their weight at their current activity level. To lose weight they then subtract a percentage off of that (10-20% usually depending on how much they have left to lose). Because this method already "counts" your exercise you can either log it as 1 calorie or not log it at all.

There's a far better explanation of this here:
http://www.myfitnesspal.com/topics/show/819055-setting-your-calorie-and-macro-targets

I don't use the TDEE method either even though I know all the "cool kids" do. My exercise schedule is just too sporadic, but I like the feeling of "earning" extra calories. If I burn 1000 extra calories with a 2 hour mountain bike ride, you bet I'm going to have extra beers that day. I don't want those extra calories spread over the week or whatever.

Mine always tells me I'll weigh more....but I've been eating at this level for over a year, and have pretty much maintained the scale weight while still losing fat.