Here is a crude drawing of the area I'm working on:
http://img99.imageshack.us/img99/9813/floors2.jpg
(The picture is enlargeable.)

I've come up with 4 solutions to this.
1) Have all the boards going left-to-right in that picture.
2) Have all the boards go up-to-down
3) Have the living and dining room boards go up-to-down, and then have the boards in the hallway go left-to-right.
4) Same as #3, but have the boards go at a 45 degree angle in that triangle I made with a dashed lines between the hallway, dining room and kitchen pass through.

#1 would be the easiest but aren't you supposed to have the board point the long-way down a room and point towards the entry?
#2 would also be pretty easy but the hallway would have the boards in the "wrong" direction and need tons of cuts
#3 would have the main room and the hallway boards going in the "proper" direction, and it wouldn't be too tough, but I guess I would need a table saw so that I could cut some boards to different lengths (they are all the same length) and then cut new tongues and grooves on them. I have some experience with wood working.
#4 would be the toughest, and I expect the little triangle would be very frustrating and take a day or two, but seeing as how I'm between jobs I've got time.

Any advice would be greatly appreciated. I can make a better drawing or upload pictures if that would help. Thanks in advance!

Quite a puzzle
Well here we go, for whatever it's worth... If it were my home I would go with #1, and ease of installation doesn't enter into it. Most of the time a customer would figure on going the long direction through the Dining Rm. & Pool Table Rm. and you mentioned that would be "pointing planks toward the Entry". Walking with the planks from the Entry door is usually preffered, ( but the planks dont go to the front door ) . I dont feel this enters into the decision with this layout. Going that direction would lead you from the entry tile, right into the steps. I would prefer to be led into the larger areas. #1 will also run planks parallel to the tile transition, instead of board ends.This will also give the Entry a look of seperation. #1 will give you a nice "flow through" going down the hall. This direction will also give the impression of seperating the Pool Table Rm. from the Dining Rm, instead of leading from one right into the other.

There's really nothing written in stone about going the long direction through a room. You have to take the whole layout into consideration.

It's really a matter of personal taste , but IMO things can start looking chopped up sometimes changing directions, ( again depending on layout ).
I especially think it would look funny going parallel then diagonal, at the "triangle".

That was the last answer I thought people would choose, but so far you, my gf, an ex gf, and an interior designer (also an ex gf...) have all chosen that one, all for different reasons. I guess I should start listening. Your reasons make a lot of sense and i hadn't thought of them. And as a bonus I don't need any new tools and it should be the easiest to do

Next question: where would you recommend I start from? Should I start with the hallway? Should I start at one end of the room and work to the other? Does it matter if I first prep everything and put down chalk lines? (It's a glue-down)

PS: does anyone know how to move a pool table? I can't even budge it.

call anypalce that sells or repairs pool tables. they will come break down for you and set it back up when you are ready around here you can get it moved and reset/leveled for about 150.00

If you dont need to buy any more tools going that direction, maybe we should reconsider!

I always prep everything first. Then chalk lines.

On that layout I would want to see a full width plank at the Entry tile. So my first run would be out from the Entry, through the Pool Table Rm.I would chalk a line from the tile through the Pool Table Rm, taking my measurements off the outside walls at the Pool Table Rm. & D.A. Then chalk a line down the Hall , off the othere line, to see where I stand in the Hall. I can then make adjustments slightly if needed. I then would know how square the tile is , & slightly trim that full plank accordingly, if needed.

Thank you both for really good ideas, I didn't think of them. I'm glad I came here and asked. So far I have moved almost all the furniture and removed half the carpet. Not sure if I will get the pool table disassembled or possibly put it onto rollers. Either way it will probably need re-leveled.

How much roughly is it to rent a sander/grinder for the cement floors? I previously put down floors in one room and used 4" razors to scrape the floor, but this it a lot more area now and I'm thinking of renting some big tools.

As for buying more tools, since I'm doing the work I'm saving money and it's like the tools paid for themselves, right?

Depending on what your scraping up, a sander or grinder may be a waste, it may just gum up. Sometimes scraping is the best option. You may want to do a little testing before you rent equipment.

If that pool table is slate be careful about putting it up on wheels I've seen slate crack
I've had people call in a company to move a pool table , move it back , and re-level it. It may not be worth the risk of moving yourself, especially if it's a 3 piece slate.