the trilogy has prophecies, factions and nightfall in 1
then buy eye of the north, add it, and you'll have all you need
you can use a fire imp if you buy any as far as i've heard, which gives you a summon to level up easier, until max level
after you learned about the game, you can buy character slots and such from either ncsoft or GW's ingame store, and maybe some costumes you'd like
also, remember to NOT throw away your keys (the codes you get with it), in case you forget your password and such
and in case you will ever buy a second account: dont mix up the codes :P
i knew someone who didnt keep his codes, and now has no access to his account, because he gave his password to someone who acted like a GM (game master), which never ask for passwords, and that account is now banned for life
(and yes, he is a stupid guy, i didnt even like him :P)
sry, was going a bit offtopic, but was for an example
if you have your GW, you can also buy the bonus weapons later on
they are nice to use for a starter character, but i only use them for my heroes now, as there are better weapons than those around
nice to see another person joining the game

welcome to GW, the game which is less active than a few years ago, but far from dead
here's something which might help:
http://wiki.guildwars.com/wiki/Main_Page
it has also the info about the products you mentioned, like the trilogy
http://wiki.guildwars.com/wiki/Guild_Wars_Trilogy
which has 1 set of bonus weapons
oh, i never knew, but if you have the money to buy this, you get everything already
http://wiki.guildwars.com/wiki/Guild...ete_Collection
the last one is good for those who never bought GW yet, which you havent yet, right?
i'm from the times when we had to pay 50 euro or so, for each campaign :P so didnt know about the last one
i hope this helps you, and good luck with and in GW
enough people on these forums who still play the game