personally, i'd prefer a mix of primes and a f/2.8 zoom.
for wide-angle, a 16-35mm f/2.8 will be good
for mid-range, a 24-70mm f/2.8 will be good
for telezoom, a 70-200mm f/2.8 may not always be practical due to its weight. i'd go with a 200mm f/2.8 prime instead for this range.
Fast primes like 20mm 24mm 35mm 85mm 200mm if shooting with buddies or alone in Singapore or Malaysia. Fast zoom (Note singular) if shooting on an overseas trip with your significant other (GF Wife). Unless your wife also happens to be a photography nut or your own very "chio" model, otherwise don't try their patience. You could end up being a patient.
I would prefer to have a few primes for specific purposes and I keep my zoom on most of the time. Many of the primes go larger than f/2 but most high speed zooms stay at f/2.8 max. If you're into low light and beautiful bokeh then primes are for you, if you want more versatility then zoom is the way to go. My few cents
It's a personal kinda thing here. If you like shooting wide open at say F1.4 or 1.2 of 1.8 then primes are the way to go. If you want to just 2 lenses that will cover nearly everything then zooms are the way to go. Personally I like the 50mm prime - it's the lens I use the most. So a zoom in that range - 28 - 85 would be good too. I normally carry 3 primes - 28mm, 50mm and 100mm - I'm not into wildlife photography or distorted super wide photography. I like the latter but to pay top dollar for a limited use lens is a bit too much for me. A nice to have but not a must have.
worth it or not is a different matter, although it is not easy to tell a photo taken with prime vs a quality zoom shot apart aperture stopped down.
For fast paced shooting or spontaneous walkabout street shooting, a quality zoom offers flexibility that is hard to beat. While i love going around with a light weight 24mm, there are so many times i missed the opportunity in split seconds the opportunity to ""zoom" a little.. I find larger aperture prime lenses of less use since i step down aperture prefocus and shoot manually anyway
Some types of photography are more suited to primes, while others to zooms
Portraits or products i think is better with primes, as you can achieve shallower DOF, plus primes are also more cost-effective
Other types such as events, or especially photojournalism, requires one to be able to capture a particular moment quickly, and in this case the versatility of a zoom makes it more suitable
Personally i like using primes, as they are compact, sharp, fast and versatile (for low-light)