I suggest you use an obscure Urza's Saga rare - more obscure than Greater Good (no offense Zadok, I mean as far as anyone who has never come to this site is concerned). I am talking about none other than Remembrance.
3W
Enchantment
Whenever a nontoken creature you control is put into a graveyard from play, you may search your library for a copy of that creature card, reveal it to all players, and put it into your hand. If you do, shuffle your library afterwards.
Of course, it might be hard to obtain this card (seeing as how the whole R&D team probably forgot about its existence a week after the set came out), but it would probably be a good addition in the deck, especially with the echo creatures. Also, if (the "if" is important) you choose to go 5C White (not that I agree with you Duel, that would pretty much change the makeup of the deck completely), Survival of the Fittest would be awesome. Picture discarding a Serra Avatar to search your library for a Serra Avatar, while the Avatar shuffles itself back in and Remembrance lets you get that one back. I suggest you either use W, W/B (for the reasons Hetemti listed, as well as Haunted Crossroads if you don't draw any other recursion stuff), or W/G.
TICM