Steven, the Janome line of machines would be a good start. The have prices ranging from $299-over $10,000.
Questions on her needs will determine specific recommendations. Does she sew garments, quilts or does she like machine embroidery. Perhaps both. Please let us know what type of sewing she does and what is your budget? There are some really good machines that are perfect garment and quilt sewing.....with installed decorative stitches, then there are those that are actual embroidery machines that you can also do garment and quilt making on. Depends on how much of the type of sewing you choose.
We can better help you with models for you to review if you post this information. Thank you so much. You wife is very lucky to have such a caring husband.