Now, I don't know about anyone else, but I am someone who learns the most by looking at data. I got bored today, and decided to make an overall comparison of all the offensive ships in ogame, excluding the deathstar. The table that I made is too large for me to put on here, so here is a link to download the spreadsheet:
HereSeveral things you need to know about this table.
1. This is a rough estimate based off of mainly one assumption:
a. Shield strength and Structural integrity help defense about equally.
2. All efficiency's are based off of the previous ship's efficiency.
3. Ships are arranged in order by total resource cost.
If this table confuses anyone, as I'm sure it will, please post questions here, and I'll try to answer them as best as I can.
One of the most important columns on this table is the last one. This one shows it's overall cost efficiency, and the higher, the better. From what this table shows, it in fact shows that the Battleship is the most cost effective ship, if only by a small margin. This is not taking speed or deuterium usage into account however, this is only based off of combat capability, so this may not be the best estimate.