First a disclaimer. This is my opinion based on my experience. Second, I do not ever recommend buying plant seedlings via catalog. Your best bet for perennials is to buy them at a local nursery or greenhouse. Four inch pots, and ideally plants that are native to your region because then you'll have less winter die-off. Your best-est bet is to drive a couple hours north of where you live and buy annuals and perennials that have experienced harsher weather than you've had. Just sayin'.
And now, Seed Catalogs!
Like peanut butter and chocolate, you get what you pay for when you buy seeds and bulbs. Pay a lot, you'll bet a better quality, pay a little, you take your chances.
Jung does a nice job, in my opinion, offering a mix of hybrid and heirloom seeds for any occasion--flowers, vegetables and fruit. They also offer a wide range of gardening accessories. Their prices are reasonable and their service is quite good. They're the LL Bean or Land's End of the seed/bulb world.
Brent and Becky's Bulbs has extraordinary selection of bulbs. Their prices are a little high, but the quality is fantastic and their service is quite good. For bulbs, they cannot be beat. They also have a fabulous catalog and offer a lot of information.
Seeds of Change offers all organic and many heirloom varieties, a lot of the unusual stuff you can't get at Jung. The prices are high, but you'll never have to purchase seeds a second time if you harvest them yourself to plant each season. They offer a wide range of products, including garden accessories. Like shopping at Whole Foods, you're paying for more than just the product here.
Gurney. Icky. They'll offer you huge discounts and coupons but their product is crap. I have a season of no pumpkins or squash two years ago as proof of their seeds' lack of fertility.
Michigan Bulb Co. This company that offers huge discounts and $25-$50 coupons for spending an equal amount of money and also offers no guarantees. You're better off buying last year's stock at your local hardware store. Seriously.
Breck's Bulbs. Ditto.
Spring Hill Nursery. Ditto.
White Flower Farm. The Nordstrom's of bulb catalogs. Gorgeous, guaranteed, pricey and worth it if you can afford it. The catalog cover is Grade A Garden Porn--the ultimate thrill for green thumbs. They're also my sole exception for mail order perennials.
Burpee. Like Wal-Mart, it's a bargain all right, but you'll get what you pay for to a degree. Not the best product out there, but also not the worst. I recommend them if you're on a tight budget.
Seed Saver's Exchange. The grand-daddy of the organic, heirloom seed purveyors. Their prices are mid-range and their reputation is excellent.
The seed packets you can buy at any big box retailer are probably not going to give you the same results as seeds ordered from catalogs. Seeds and bulbs purchased at a greenhouse or nursery are a better choice if you can't order from a catalog.
And now, Green Girl must return to peacekeeping duties because Team Testosterone is hepped up on too much Valentine's Day candy.