Being someone who has completed about 100 quests, the vast majority in Qeynos, I consider myself somewhat informed on the topic of "good quests". Many of you may be wondering which ones you should participate in. I personally recommend doing as many as possible. It's great experience, and even if you can't use the item, you can sell it to an NPC or another player. There are a lot of quests out there for the same item (i.e. toxic bog slugs). Try to get as many quests as you can that involve a certain area (i.e. Peat Bog) before going into it. That way you can kill multiple birds with one stone and save yourself time. Here are some of the ones I recommend (for more information, see the quest guide on this site):
Tour of Antonica -- Antonica
Great 10 slot backpack but what a pain in the **** as far as running around tring to find ALL of those points on the map.
Bear Fashion -- North Qeynos
Great armor quest!
Dyes for Daniells -- North Qeynos
Same shop as the the NPC for Bear Fashion. For only being a delievery quest, this isn't a bad item.
The Balance of Life --These aren't bad quests. I solo'd the 3 sets of mobs I had to kill in my mid teens. They could easily be grouped at an earlier "age".
An Ode to Oakmyst -- Oakmyst Forest
I forget the item that I obtained but I remember it as being worth the trouble of running around to the various sites. Be careful of the last stop though (the cave). The dryad's there were gray to me in my mid-teens but I'm sure it could get tough at a lower levle.
Cleaning Supplies for Findlebop -- Baubleshire
Considering that you only needed one kill for this quest, it's not a bad armor piece at all.
Dane Steelfist, Beurocrat -- Graystone Yard
This is an excellent quest that is conducted as a set 3 missions from the dwarf on the 2nd floor of the tavern. It is definately worth buying the dwarven language book at the scribe (12sp) to get the boots which are the end result of this quest.
Captain Elgrondeth's Dilemna -- Nettleville
This quest was a bit long and drawn out for the reward but considering the exp you get along the way, it was worth it.
Refil the Oakmyst Spider Sack -- Netterville
Again compared to what you have to do to get this, it's not a bad quest.
Substance Extract for Yanari -- Castleview
This is an excellent quest for the adventure fresh off the boat from IoR. I wore the armor reward until I was able to complete the "Bear Fashion" quest.
Proving Yourself to Captain Garathalas -- Castleview
Again, another great armor quest for the brand new adventurer.
These are just a few. As I said, I recommend looking at an area (say Oakmyst) and seeing what quests involve that zone (not just start there), then run around, grab thoses quests, go to Oakmyst and do them all at once. You can complete 2 or 3 quests objectives off of one kill that way.
Now there are some bad quests out there that just aren't worth the effort. One in particular that comes to mind is Journal of Elkare (Eldar Grove). The group of bandits you have to kill (that spring from the tree in Antonica) were yellow to me at 15 and the quest reward was only green or blue as an armor piece and not worth much on the market. It took me forever to get a group together to finally beat them and it wasn't close to worth it.
I hope this helps someone. I know when I first started, I wanted someone to recommend good quests to me and all I got was "read the quest database". Sometimes taking the time to impart a little bit of wisdom can go a long way. Although I would like to say that I appreciate all of those on the board who have helped me with questions the past few weeks.