FInd out what the billing requirements are at the firms you are interested in, that will tell you how many hours you have to work. A 2000 hour billing requirment is going to run you roughly 60-70 hours a week at work, depending on how much nonbilling stuff you do (like eat, development, firm meeting). 1500 is going to run you about a 40 hours a week, both assuming you take 2 weeks vacation and holidays.
This is exactly why you shouldn't rely on this board to answer your question...ask a real lawyer, somebody in a big firm who actually bills 2000 hours/year.
To say that in order to bill 2000 hours you have to work 60-70 a week is utterly retarded. Let's say you work 48 weeks out of the year...2000/48 = 41.6 hours/week...so assuming that you bill 80% of your time at work (which is a standard at many firms), you would have to work 52 hours per week. Some weeks may require 60 or more, but average at my firm is ALWAYS under 60, and sometimes under 50...and its still possible to bill 2000.
Don't forget, pro bono work can often be included toward billable requirements (sometimes in upwards of 250+ hours). Think about that.
Jacy is right, I should say you average around 60-65 a week over the course of a year, sometimes less sometimes more, but to say you can consistently bill out 80% of your time is uterrly retarded.
If your billing 80% of your time at work your either not taking a lunch, an office shut in, at a big firm with no nonbillable meetings (think 3 hour profossional development meeting or name partners 2 hour chamber of commerce speech on asset protection), have no CLE requirments, or bullshiting billables. Either way you are going to be the biggest loser at your firm or burn out after a couple of months.
If you take a 1 hr lunch, a 50 hour week will give you less than one hour a day for nonbillables. Not gonna happen After a coupke of years you can bill more in less time (like a 6 hour block at court or 2 day trip to another city to attend), but initially, a 2000 year is going to run you average 60-70
Also just because you bill 2.5 on a project does not necessarily mean you will get credit for the full 2.5. A partner is going to approve the amount that will actually be billed. Different firms treat unrealized billables differently, thay may count for perfomrance reviews but not bonus requiremets.