i used a regular DX aviar 149g when i first started and still do i would suggest the aviar, something simple nothing crazy, to start out with and if you feel like going more adventurous hit up the some of the other putters that are out there
but what it really comes down to is just get 3 of the same one and same weight (or just one) and practice as much as you can with it so you know how it files and feels and then you'll be set
Omega Super Soft
SSS Magic or Voo Doo
JK Pro Avair (on the overstable side)
When I first started I tried just about every putter and then settled on a Wizard or JK Pro Avair. Since then, I find that I've become much more consistant with a nice neutral putter (APX Swirl). I think it's either a 0.0 or .5 stability on the Discraft chart. IMO, they track straighter and hyzer less, so to me the are more accurate. Some say they don't handle the wind as well, but the more I play in the wind. The more I find it's more of a mental challenge. I'm not saying you can use them from 75' into a 20mph headwind, but for me they are fine from 40' or so.
Now after all this talking. This is what works for me and as I've said before. Putters are the hardest discs to reccomend imo. Due to the fact they have to feel good/right in your hand so you are comfortable with them, and to me. Thay makes for more birdies!
If you haven't heard of this site (discgolfreview.com) They have tons of reviews on all discs as well as instructional stuff.
Discraft magnet. It's a neutral putter used by many. The apx would be another suggestion. I started with a challenger and though I love em now, I think it was a lil too overstable for me then and promoted me spin putting to account for the hook.
I enjoy the Vibram putters. I have a Ridge and a VP is the softer of the materials. They're awesomely predictable and pretty forgiving. The part I like most is that they have almost no glide, so if you are staring a do-or-die/death putt in the face you can have confidence that even if you miss the basket at the top link you have a wicked good chance of that putt falling to the ground in less than ten feet. When I putt, I putt with authority but unless I am trying to send this putter off like a midrange with tons of snap behind it, it won't go far past the basket.
There's a reason that the Aviar and Magnet are industry standards. They're both great putters that will serve you your whole career. Gateway's Magic, Latitude 64's Pure and Discmania's P1 are all quite similar but much harder to find.