Hi Ahleha,

What type of camera system do you own? I think that you definitely want to cover the basic ranges...and if you are on a budget, you may want to consider some 3rd party lens manufacturers.

For example, Tamron's 28-75 F2.8 is very well rated and 1/3 the cost of Canon's or Nikon's professional lenses. For the ultra-wide end, Sigma's 10-20 lens looks very good (I have the Canon 10-22 and it is also pretty good given the limitations of the glass). Sigma's 80-200 is an excellent lens and very affordable. With the cropped frame sensors, in the Nikon/Canon cameras, you will also get a solid telephoto with it.

Olympus on the other hand has its own top quality glass and covers very different ranges....i.e. Their 14-54 matches a 28-108 zoom range...all in one lens.

Take care
James