I would have to say a tiel since I have never had a lovie or a budgie...and because they are my fav (if you can't tell my my sig lol).
They are great little birds and if you get a hand tame one very sweet and cuddly.
I have heard that lovies can be nippy..but it depends on the bird of course. It would be alot of work if you do decide to get a bird that hasnt been hand tamed but it can be done..there is a better chance of taming a young one too..but there is always a chance that the bird will stay wild though so I would get a hand fed one if you can (or one that has been parent raised but socialized..a parent fed baby can be just as tame if the breeder actually takes the time to socailize it). Good treats are cereals that arn't real sugary.. like cheerios or stuff like millet.
B&G Macaw- Charlie
Cockatiels- Jay Jay, Jackie, Zazu, Precious, Luna, Dakota, Cosmo, Teasel, Jasper, and Layla
Cats- Bosco, Bear, Max, Abby, Buddy and Molly