If you aren't certain what to brew, consider what would do well for the season. Assuming you are in a temperate zone North of the equator, and don't have a fermentation chamber set up, I would recommend something easily brewed with heat tolerant yeast - which pretty much means either a weizen or a saison. Fortunately saisons are both flexible and dominated by yeast character, so if it is a style that appeals to you, it should be no problem to find an extract based recipe for one.
On the other hand, if you are in the Southern hemisphere, or have good temperature control, your options open up considerably. In the former case, something suited for late winter or early spring should be considered. In the latter, you can choose more or less anything, though a summer or early fall beer would make the most sense.
Of course, there are some things which are suited for any time of year (if you have the right temperature control for fermenting it). A pale ale or brown ale is pretty much general-purpose, if they are styles you enjoy.
Beyond that, I would say, browse the recipes here and at similar sites until you find something that catches your interest. If all else fails, you can try the following (all measurements in US measures, convert as convenient):
Flemique Pale (Belgian Pale Ale)
6.5 lbs pale LME
1 lb. 45L crystal malt
1/2 lb. Vienna malt
1/2 lb. Victory malt
2.5 oz. Hallertau (4.5% AAU) pellets, First Wort Hopping
your choice of Belgian ale yeast - I recommend either Belgian Golden Ale yeast (White Labs liquid yeast WLP570) , Mangrove Jack Dry Belgian Ale Yeast M27, or Belgian Abbey Yeast (Wyeast 1214)
expected OG - 1.050, FG - 1.013, ABV 4.8%, bitterness - 26 IBU, color - 12 SRM
Heat 2.5 gallons of water to 165F. Add crushed speciality grains and hops in mesh bags to water, steep for 20 minutes. Remove grain and hop bags, bring water to boiling and stir in LME. Boil wort for one hour. Top up water to 5 gallons. Cool 75F or cooler, pitch yeast.