As CB said, sail boats are all compromises, and I think that is not really understood by most people when they first start looking around.
There are couples sailing the world on small, inexpensive 24' boats which are very sea worthy and very cramped, but they are having a blast. Then there are single handed sailors with $500,000 45' boats who could not imagine doing it on less. The important things when deciding where you are on the spectrum is to figure out what you can afford, what you must have, and what must haves you can give up to make the too meet at a place that makes you happy.
Some absolutely need a separate, stand up shower with hot water and enough tankage to take a shower every day. Others are happy with a couple cups of warm water in a bowl and a wash cloth every few days. Which are you, and are you willing to compromise if needed?
Sailnet has a wealth of information and view points on all sides, and reading books from cruisers can help a lot to. Just remember that for many things, if you ask 3 sailors, you will get 4 different answers on the best way to go.
I have not done any real long distance sailing yet. but we plan to take an extended 1 - 2 year trip very soon, in the next year our two with my wife and two daughters on our 32' Islander. Most people think we are nuts, and that we will not be happy with out a 45 - 50' boat. They may be right, hopefully we will find out soon!
My basic list of MUST HAVES is this....
1. Strong hull and rigging.
2. Seaworthy design (Many opinions on what that means

)
3. Dedicated sleeping for all permanent crew.
4. Enough room for all four of us to sit below comfortably.
5. An enclosed head.
6. An oven (I love hot, fresh baked cookies and bread)
7. A Dodger
8. Comfortable cockpit.
9. Ability to for me to stand upright in the main salon.
These are MY must haves, I know many would not require some things on MY list, and others would add A LOT of items to THEIR list. You will need to get out and sail and spend time on boats to decide what is on YOUR must have list. Just remember to keep the MUST HAVES truly MUST HAVES, move anything you possibly can to the NICE TO HAVE list.
For me, all else is negotiable. Exact length, electronics, showers, sail plan, engine type, etc. This does not mean I do not want any of these things or ave strong opinions, just that these are areas where I am willing to compromise and take trade offs. I would like three separate cabins, but want a boat one person can sail, and have a limited budget. Therefore we ended up with a v-birth and 2 quarter births open to the main salon. Good enough, and affordable for us.
We managed to find all this for the four of us in a 32', inexpensive boat, but it took a lot of looking. Compared to the 21' boat we had, this one is huge. Of course, 2 more feet would be perfect, but that is always true.
Anyway, good luck and have fun learning what you want, that is half the fun of buying a boat I think.