there's reasons to buy it, but i dont like to see people spend their money on a game they may not like, due to inactivity of lots of people so:
with GW, you can fill your HoM to gain more in GW2
you can probably find some guilds still alive, but its rare
dont expect that much of this community anymore, and thats not about them being bad, more that most people who were playing, are mostly gone now
but hey, look at how old GW is, almost 7 years old now
if you're good at playing just with heroes, looking at guildwars wiki alot and barely having chats, it's a great game for you
also: maybe you would find some nice people, so dont take my words seriously for 100%, as i have searched for friends/guilds some time ago, and couldnt find any normal ones, and normal ones are (to me) guilds which just help you for free and have enough time to help with either easy things, but also hard stuff
problems i've seen:
- they have done something you may need help with, so they wont join you, as they have done it too many times (you know, the "again? no thx" attitude)
- people are rather busy with their own stuff, instead of helping you out
- people become inactive, and even if they get on, they barely show themselves, as they have done everything they wanted in GW anyway
- people leaving not long after i met them, as they (again) have done everything, and think GW isnt worth their time, instead they wait for GW2
in short: as far as i've seen it, people are waiting for GW2, and dont bother to do much in GW anymore
sidenotes: i'm not saying everyone is like that, just most people i happen to meet (which is no offense)
so there may be some active guilds around, but you never know for how long
i'm not counting the elitism in GW, as all MMO's have it, some MMO's even worse
so imo it'd be: dont mind playing alone for some time? (maybe a long time, depends on how fast you find friends/guilds) and dont mind to meet up with people who dont play GW that much anymore?
if you dont mind these points, you could buy it
and as someone said: you better buy em all, like trilogy pack + eotn, as that way you have everything, which gives you alot more to do, and that way you can find friends/guilds easier (weird but true)
my tip: if you have it all, start playing in every campaign (the ones from the trilogy pack) and see where you like it most, and find out your best profession
then once you know some of the basics, you can start finding people to play GW with
and important:
http://wiki.guildwars.com/wiki/Scam
with this page, you can find out about scams, so they wont get your money in no time
and in all MMO's there's 1 rule: never give your account info (or reallife info for that matter) to anyone even if they say they are a GM (game master)
ps. click on the shield of that page to return to the main page of the wiki, and use it as your guide
also, ask for advice and/or help on these forums in the right sections, cuz even with a small amount of players left, you can get help
good luck with choosing, and if you buy it: also good luck with GW
oh yea, about me: i play this game for more than 6 years, so i kinda know whats going on