Agreed, you can do web development on nearly any modern laptop. There are more important things to focus on, besides horse power.
1. Solid state drive. One of the few upgrades you'll notice day to day.
2. Portability, and screen size. After a handful of laptops, I've settled with a Samsung Series 9, 13.3", 2.8lbs. I'm constantly on the road, so it works perfect. If I'm home, I just HDMI the display to my 24" monitor and keep working.
3. Display. The Samsung I'm running uses PLS, similar to IPS, so it doesn't matter if you view it head on, or any angle, the colors and lightness remain accurate. This is incredibly important for any type of design work, and on my prior TN laptops, I'd be bending my screen forwards and back, trying to dial in subtle differences in color.