my pick for best custom races.

best custom opper race : slut lominar 2987
Furbies
There brown and fuzzy and have a bad temper   

Population growth: -30%
Income: -30%
Research: 50%
Attack: -30%
Magic: 50%
Speed: 100%
   
Spells
Hypnotize
Reduce Food Production
Electric Storms
Kill Scientists
Find Target Planets
Space Amazement
Destroy Iron

Operations
Spy on Target
Place Nukes
Destroy Units
Sabotage Portal
Investigate Portal
Planetary Infrastructure
Destroy Cash

Specials
Droid

verdict : excellent race to play with if you dont like the stress of attacking and fear of getting raided. works perfectly well for resourcing while providing an all rounded opp-ing service for your fam. i like the selection of the droids, it makes a good retaking option as well. generally a good support race to play in the fam.

best attacker race : incredibad 2985
Trespassers WILL be
....Survivors will be shot again   

Population growth: -30%
Income: -30%
Research: 50%
Attack: 50%
Speed: 100%
   
Spells
No Fear
Find Target Planets
Space Amazement

Operations
Infiltrate
Destroy Units
Sabotage Portal
Investigate Portal
Planetary Infrastructure

Specials
Droid

Verdict : this is the custom race every attacker should look at. most have similar % for the race but different choice of ops. this race has the ops which is very beneficial to every attacker. infiltrate,pi,ip to plan your attacks and sab,du to support your attacks. However, i think ftp and sa can be substituted for some other ops like place nukes and destroy cash. otherwise +10%magic would be good also for resistance against cpffs. HC attacker generally dont have large planet sizes, so sa will not be really significant and ftp can be done manually otherwise a pax can always do it for you.

best banker race : none IMO, If you really have to, below is one of my choices.
best custom banker

Population growth: -30%
Income: 50%
Research: 50%
Attack: -30%
Magic: 10%
   
Spells
Space Amazement

Operations
Planetary Infrastructure

Specials
Tax Office

Verdict : i guess bankers are rather vulnerable if you have -30%magic. be it pop banking or cf banking, an OH or estorm can easily knock you down. predefined races such as pax would do a fine job, less the income bonus. sacrifice the income bonus for more security and defence. An op like pi is usually very useful. And the banker can help out with the attackers in addition to their banking duties.

--i have seen many disastrous races which are crap, so I have decided to come out with this thread and some races for reference purposes. Feel free to post your best custom race and views.