almost everyone subsequently posting is going to probably tell you to get one of the following: Grammostola pulchripes (chaco gold knee), Grammostola pulchra (Brazilian black), or Eupalaestrus campestratus (pink zebra beauty).
i have no experience with E. campestratus, but i do have both Grammostolas and they are similar enough to Brachypelmas as far as growth being on the slow side, drier habitats, etc if not possibly a little more laidback. none of my Grammostolas have kicked at me, unlike my Brachys, many of whom are repeat offenders! (they've since gotten a lot better about it as they have grown though.)
did you want to explore Brachypelma further? i found that mine have different temperments to a degree, and thats kind of cool. my vagans is crazy, the smithi pet rock-y and the boehmei is an adorable oddball (he's my favourite out of the five).
lastly, if you want to spice it up, Lasiodora parahybana could be a nice change. they are super cheap as slings, grow fast, stay out (if your Brachy is a hidey-hole you might like this) eat great and grow huge. you already have dealt with Brachypelma spp. urticating hairs (i am assuming) so the LP hairs wont be a huge surprise to you as being quite itchy. they can also be a bit more defensive than anything previously mentioned, but usually pretty managable. some people have talked about having ones sweet enough they suffer the hairs to handle them, but that's not something i'd personally do.
Yes I agree going with the L. parahybana, that's if you're going the sling route. If you're going the Juvie route, I propose an Avic of some sort. Namely A. metallica. If you're looking for an adult, G. pulchra.
Many doable choices. Depends what you want. All the recomendations are do-able. B Vagans are inexpensive, faster growers, better feeders, and more interesting than most Brachys. GBB's are FANTASTIC spiders. Great color, great feeders, fast growers, and very interesting. They are, however, kinda skittish. Just watch out for the speed! They are kinda pricey, too. LP's are inexpensive, hardy, kinda skittish, faster than most "teddy bear" terrestrials, fast growers, but get HUGE. At full size they almost make a medium-sized T look like a wolf spider by comparison.