Seeds vs. Starts

This is extremely dependent on your level of time, commitment and interest. I cannot tell you what is best but I can tell you the pros and cons for you to figure out what might work out best in your circumstance.

Seeds
Pro:

• Inexpensive
• Easy to come by
• Many varieties available that you might not find at your local nursery as a start
• Fun - very rewarding to start a plant from seed and eat from it 4 months later

Con:

• They take up a lot of room in seed trays to get started (at least 1'x2' each)
  
• Need warmth and sun - these are non-negotiables
  
• Require planning; need to start seeds 3-4 weeks before you plan to put them in the ground
• Come in absurd numbers; you might not be planning on planting 100 cucumber plants this year and seeds only store a year or two under good conditions so it might be more wasteful than beneficial

Starts
Pro:

• Already started!
• Usually can go right in the garden when you get them home and with a little TLC and lots of regular watering they will start growing immediately
• Allows smaller purchase quantities; if you only want one basil plant it is a lot easier to get a start than to labor over three seeds for one plant.

Con:

• Expensive. A seed packet of 100 seeds may cost you $2.50. One start will also likely cost about $2.50. Again your garden size matters here more than anything.
• Limited; your nursery will have maybe 4-10 different varieties so your options are fewer than with seeds.