The best replacement for iphone 3 is iphone 4.

The best alternatives to iphone 3 are rated as following:
★★★★★  iphone 4
★★★  blackberry torch
★  samsung captivate
  samsung focus
  iphone 4 review
  iphone 4 specs
  iphone 4 size

Your alternative for iphone 3 is not listed? Suggest!
Speaking about iphone 3, one probably shouldn't forget about ios 6.

Other search terms related to iphone 3 and their ratings are:

★★★★★ ios 6
★★★★ ios 5
You have in mind a companion for iphone 3 and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of iphone 3 in all years. Click on graph for more.
iphone 3
iphone 4
blackberry torch