So I have this super nice four year old, I am going to retire her next year as a five year old, unless the rest of her year is stellar. This year she won one Grade 1 stakes, 3rd in another Grade 1, 2nd in an Ungraded Stakes and has had a really nice 2, and 3 year old career. She is best over 8-9 furlongs on the turf, her sire and dam were both created. Does anyone have any ideas as too who I should breed her too?
Having her name would be a good start! 
Then we could see her pedigree and give some suggestions! 
Anyone, with that pedigree. Worth or Rogue sons are pretty tried and true. It depends a lot on what you can afford and what you want. I’d check out stallion rankings for established studs , the eclipse awards/hall of fame for newer studs/new ideas. Eclipse awards can give you an at-a-glance idea of what that horse excelled at. If you’re feeling adventurous, breed to a stallion fresh off the track. I feel like first crops tend to be the most successful (don’t know why, and I have no proof that this is the case), and it’s a cheap way to get in on the ground floor of what could be an amazing stud (or an awful dud). Just a reminder, price is not necessarily a measure of quality.
You might have luck with studs in their sophomore or junior year. Since they’re no longer fresh off the track, they might be easier to snag a spot with, and they’re still not proven so fees will still be pretty low. For example, my stallion, FFCh. High Chances, will be in his 3rd year of stud in 2014, and it’ll probably be the last time he stands at $15,000. His first crop will race next year, and, provided that they do well, I will most likely be raising his fee in 2015.
The stallion stats page might prove helpful as well. Everyone has their pet stallions, based on their own experiences with their own racehorses. The stallions I like typically have given me successful runners in the past. Your mare has no in game lines, so she can breathe with anyone you like.
And you might want to seriously consider running her as a 5yo. My 5yo mare who was frustrating as a 3yo and mostly as a 4yo, too, just took 2nd at the BC on Monday… I can’t tell you how many times I threatened her with retirement, and for some odd reason I kept running her. Thank heavens I did!
Good luck. Hope this helps.