24 inch vs. 20 inch: Is bigger REALLY better?

Hi,

I have (at least) two questions here. First of all, I recently purchased this 20 inch iMac (2.66 GHz). I am coming from a MacBook Pro 15 inch and now I am considering exchanging the 20 inch iMac for the 24 inch iMac (not sure yet: either the lower-end 24 inch or the higher end 24 inch). I have already migrated and set this one up. I am not even sure if I CAN exchange. I will have to call Apple to find out. I am just wondering if people think that it would be worth the exchange and the head ache of packing it up, sending it back, waiting, and of course spending more money. I researched for days and I was under the impression (after measuring) that the 24 inch would not fit in the space that I intended it to go. I was fine with this because I am used to the 15 inch screen and was happy to be spending a bit less money. After getting this one here, my husband asked me why I did not get the bigger screen (after I am sure we discussed this) and then proceeded to show me that it would actually have fit and that I must have measured wrong. It will only fit with a quarter of an inch on each side! Now I am just torn. I personally am fine with the size (and I am the main Mac user in the family). I have no need for superior graphics as I only do internet and word processing. I am thinking that the aesthetic will look better because it will be like a custom fit in the space I have intended for it. It is the three guys in my life (husband, and 2.5 year old twin sons) who have assured me that the bigger one will probably be better. Do you think they are right or not?

Another minor question: When I ordered this mac I signed up for the Apple Care Protection Plan and I did not receive any information on that with the computer. How do I know if I have been enrolled?

Thanks.