A List of Recommended Addons for Classic

1. Immersion: Needless to say, an addon that converts quest texts into a readable dialogue window.

2. Questie: An addon that tells you roughly where quests are. It has the advantage of marking, in small notations on the map, where to receive quests and, for collection quests, where you can collect items. More than anything else, having this addon lets you reduce your travel route a bit.

3. SexyMap: An addon that lets you use the minimap with a slightly different design.

4. Vendor Price: An addon that tells you item prices in advance. For reference, in Classic you can't know the prices of junk items until you go to a vendor.

5. Threat Plate: An addon that shows you threat levels. Nowhere in Classic is there a 'number' that lets you know threat levels at a minimum. You can learn this through the addon. Think of it as similar to an aggro meter.

As for the rest, there's nothing worth recommending yet.

In the case of Azeroth Auto Pilot, a Classic version is available. If you use this, you can take a relatively fast quest route, but it isn't perfect, and on top of that this addon tends to eat up a lot of memory.