vocabulary - Fun with synonyms - "eternity"

What are the differences among the following two-kanji words that seem to mean "eternity":

• 永遠 {えいえん}


• 永久 {とわ}


• 永世 {えいせい}


• 永代 {えいたい}


• 永劫 {えいごう}


• 永永 {えいえい}



• 久遠 {きゅうえん}


• 悠久 {ゆうきゅう}


• 恒久 {こうきゅう}


• 恒常 {こうじょう}


• 長久 {ちょうきゅう}


• 無窮 {むきゅう}

Please include any other related words (preferably two-kanji only) but please exclude those that make use of period of a lifetime like 一生, 末代 etc, or big number of years/era like 千代, 万古 etc.

p/s: I noticed that the first two 永遠 and 永久 are the most commonly used; is it true and why them instead of the others?