If you cook frequently I highly recommend purchasing a nice chef knife. A good, properly sharpened knife just makes things so much easier and fun. It is also much safer. A dull knife may or may not cut the way it should.
As for sharpening, it is a world in itself and if you're not into it you can just swing by one of the pro sharpening places around town and you'll be good for 6 months if cooking often, possibly longer, especially if you maintain the edge with a honing steel.
Starter western style chef knives: Victorinox, Zwilling, Wusthof
Starter Japanese style knives: Tojiro
Starter sharpening stone: King 1000 grit