Dennis, exploration is important early in the game, so you probably would have been better off building at least one warrior to explore, prior to covering your butt with a hoplite.
Researching warrior code for defense is fine, as you can immediately build archers, but there are arguments to be made against it. You could have researched iron working, which would give you better offensive units, although only if you had iron handy. As a rule, it's better to research ahead - no one has iron working or writing - as opposed to parallel (warrior code), if only because you can probably trade for it as soon as you encounter another civ (with that exploring warrior!). In the case of Greece with its hoplite, however, you could argue that you don't need offensive units for defense (if that's why you're building them).
You built roads in all the right places, which is good, but you didn't mine anything, which will slow down your productivity. Had you mined that first grassland, for example, you could have had an extra warrior, and still build that settler just as your pop hits 3. Improving squares almost always means both building a road plus either mining or irrigating it.
The site you've chosen for your second city is okay, but not optimal. Building near the luxury resource may be a better bet, although you don't need its benefits so early at regent level. However, both of these easterly locations are relatively secure, because they're bounded by water and your capital is in the way from the other side. It generally makes sense to build toward the AI, which in this case means heading west fo now. The reason for this is that you thereby take territory that's likely to be contested, making your empire bigger at your neighbor's expense. Then you could "backfill" those eastern city sites later.
Finally, if you're not expansionist it's dangerous to pop huts without proper defenses, as you just discovered - that westernmost barbarian is about to sack Athens. The hut wasn't going anywhere, so you should have waited to open it.
It is used in GOTM and other SG's, is it not? The situation of being able to spot a resource that one *might* not not be able to see under FoW with standard terrain is the only situation I can think of where it is an advantage, although Cracker in his Opening Moves strategy articles points out how you can see them if you look carefully enough. Besides, we are only playing to learn here, right? 
!! 
Begin Hoplite.
