It depends on what kinds of things you want to do in addition to quilting. Do you want to do decorative stitching, embroidery? If so, you do not want a long arm since those are straight stitch only. You do not need to have a long arm to quilt large quilts. Before I bought my PQ1500s (9" harp space, straight stitch only) I quilted double and queen sized quilts on my two smaller domestic machines (7" harp space). If you are planning on Free Motion Quilting, or using your walking foot to quilt, then you don't need hoops to machine quilt.
In addition to thinking about whether you want a machine that does more than straight stitch, you need to think about budget. There are domestic machines on the market now that do lots of decorative stitches and have anywhere from a 9" to 12" harp space. These start at around $1500 and go on up from there. To get one that also has embroidery features you will be looking at more expensive machines.
A straight stitch only machine with a 9" throat will run from $600 to $1200 or so depending on the manufacturer.
Two features that I like to have when I'm FMQing are needle down and either a good responsive foot pedal that allows me to easily control speed or a speed control on the machine itself.
Rob