There's plenty better, but it does depend what you want. Views, beaches, history, walking, resorts/touristy or traditional, as a couple or a family? Will you hire a car or rely on public transport &/or trips, looking for a package or DIY? If it's a package where can you fly from?
With so many islands, not to mention masses of mainland there's a wide choice out there.

I would like somewhere thats pretty, not too bothered about beaches. Dont mind it being slightly touristy but not full of teenagers and twenty year olds!
We are looking for a relaxing holiday and may hire a car to look around but not too bothered. Some nice tavernas and bars/restaurants for the evening.
Also dont care if its package or diy.
This would be a couples holiday so any suggestion would be great!

Lesvos, package or DIY, if package try & stay in Molyvos, or at least Petra, I would say not Anaxos (these are mostly the only 3 available on package). Great non touristy island on the whole, but large & diverse in scenery & a car is a real benefit. If you go DIY consider staying in more than one location (we did 3),
http://www.flickr.com/photos/yiassas/collections/72157625192196112/
Naxos, stay in St Georges area, close to beach & town (including the old part),
http://www.flickr.com/photos/yiassas/sets/72157619603448627/
Amorgos, Sifnos, Folegandros (most of the Cyclades actually), many small & pretty islands. Mykonos is very pretty, but expensive, & can be very busy & touristy at the height of the season or when cruise ships dock for the day,
http://www.flickr.com/photos/yiassas/sets/72157619613788431/
Rhodes, love the Old Town,
http://www.flickr.com/photos/yiassas/sets/72157622599457095/
Many love Lindos on Rhodes & return year after year, not my cup of tea though, too touristy & 'twee', again gets swamped with day trippers/cruise passengers during the day, but the Acropolis there is worth a visit,
http://www.flickr.com/photos/yiassas/sets/72157622723670252/
http://www.flickr.com/photos/yiassas/sets/72157622723665786/
I've just realised that I couldn't have been that taken with Lindos itself, I don't think I took any photos!
Then there's the Peloponnese,
Koroni,
http://www.flickr.com/photos/yiassas/sets/72157618268039766/
http://www.flickr.com/photos/yiassas/sets/72157623948199309/
Finikounda,
http://www.flickr.com/photos/yiassas/sets/72157620720135544/
The Mani (Stoupa, Agios Nikolaos, Kardamyli, Gythio, Areopoli etc),
http://www.flickr.com/photos/yiassas/sets/72157624028492509/
http://www.flickr.com/photos/yiassas/sets/72157624153116578/
http://www.flickr.com/photos/yiassas/sets/72157626392455619/
http://www.flickr.com/photos/yiassas/sets/72157626523859178/
Further east on the Peloponnese, there is Nafplio & Monemvasia,
http://www.flickr.com/photos/yiassas/sets/72157626513547152/

I think I'll stop for now! I hope there's a few places there for you to think about, bear in mind that almost anywhere would benefit from at least a few days with a car.

Quite a few suggestions there, but my personal favourite and also quite a few others on here is Parga. Lovely place that has something for everyone, but enjoyed mostly by couples. The only thing is as it is the mainland people have said it is dearer than the islands. (mainly in the cost in getting there) I also like Halkidiki.

I've just got back from a holiday in Naxos. It is a fantastic place, the best Greek island I have been to and I've been to about 14.
Naxos town has a wonderful beach with plenty of tavernas and sun beds. In the town itself there are plenty of good tavernas and bars and ice cream parlours.
One of the nicest things was the lack of Brits, there were Dutch, Canadians, Norwegians, a few Germans.
I hired a Jeep for 2 days and went round the island. The roads were quite good, the scenery beautiful and the scent from the wild herbs was heavenly.

I like Naxos a lot!

we are off to Samos in 4 weeks and have heard that it is quite senenic. Haven't been to Santorini but have been to Kefalonia which I though very pretty but there was something missing with the lack of old buildings

that's the thing i found with kefalonia,and zante also,there's no ancient sites or historic buildings at all following the earthquakes of the 1950's and before.

Rhodes is my recommendation,i'm biased as it's home but it's got everything you need and can be as commercialised or as traditional as you like,just pick your place and avoid staying in chain hotels.
Kiotari is nice

For me every island is special and bautiful. I've seen more than 30.. I love Sifnos!

Been to quite a few Greek islands/mainlands....Kephalonia x 3...Rhodes...Naxos..Crete...Corfu...Mykonos ..Lesbos...Parga...Zante.etc etc...but this year was Paxos....THOROUGHLY recommend it...I'd say Mykonos would be second.

How about Skopelos? A lovely green island with friendly locals, and despite THAT film it hasn't been overwhelmed by mass tourism. There are some beautiful low key resorts dotted around the island and Skopelos town itself is gorgeous with lovely tavernas tucked away among the narrow back streets!

John