I'm not sure which brands are good, but I have a Kenmore and I wouldn't recommend it. My machine gets jammed with thread all the time and isn't very good for sewing heavier fabrics.
Years ago I bought a Bernina that was top of the line except it didn't work with the computer. I didn't want that feature and I am so glad because the computerized model used floppy disks. Akkk! So remember the march of time and technology when getting a machine that you'll want to be able to use far into the future. Like my beloved Bernina.
@Kate I find that interesting. I have only ever bought Kenmore machines and I love them. All Kenmore products are actually manufactured by other companies. I believe their sewing machines are made by Janomi because the presser foot for my Janomi serger is exactly the same as my Kenmore machine. Features that I recommend looking for are one-step buttonholes and stitch settings for knits. Those were the two major things I looked for when I got my second machine. I recommend going to Jo-Ann's and test driving a few different machines. That way you can decide what is best for you. Starting next week I believe, Jo-Ann's is having a buy 1 get 1 free sale on their Simplicity machines.
If you're a dedicated sewer you want to make sure that the innards are made of metal rather than plastic, but other than that caveat I agree with Sarah.
I have an old Singer Stylist from 1979. I've had it for about 13 years and I've only had to have it serviced once. Most of the innards are metal, which is awesome as well. If you decide on a model, make sure it can accept specialty feet (like a button hole guide, invisible zipper foot, or walking foot). You also want to make sure it has some sort of button hole feature. I prefer something simple, so I wouldn't bother with one of those computerized models.
Go and test--it's the only way to decide which one you like the best. That being said, I have both a (very old) Singer that I LOVE and a Baby Lock Serger which I'm learning to love.