They do have some good young players however they had arguably the worst GM ever in Mike Milbury who set them back pretty far.
Here is a nice list.
1- Roberto Luongo & Ollie Jokinen for Mark Parrish & Oleg Kvasha, then passing on taking Dany Heatley or Marion Gaborik and instead drafting Rick DiPietro at # 1 knowing he would have been there at # 5.
2. Zdeno Chara & the draft pick that would have been #2 and probably Jason Spezza for Alexi Yashin. Then signing Yashin to a 10 Year contract, that had to be bought out by the Islanders because Yashin's production was so poor.
3. Trading Todd Bertuzzi & Bryan McCabe for an old, slow Trevor Linden
4. Taking Robert Nilsson over Zach Parise in the 2003 Entry Draft.
5. Trading Raffi Torres for Janne Niniimaa
6. Letting Martin Straka go on waivers rather than signing him for 40K
7. Trading JP Dumont to the Chicago Blackhawks for Dimitri Nabokov. Nabakov played all of 30 games for Islanders amassing 4 goals & 11 assists.
8. Drafting Michael Rupp with the 9th pick of the 1998 draft then not signing him to contract. He went back into the 2000 draft and was picked by the NJ Devils with a 3rd round pick. He is still playing for the Devils today.