Ranger Animal Companion modification?

[Bauglir]

What, if any, changes would you guys make to an animal companion (gained at level 2, but otherwise using the Druid's progression) to make it a comparable beatstick to a Fighter without bonus feats? The animal companion gets no magical equipment (assume no spells are available to buff it, either), but must keep up its stats as though it got standard numbers buffing equipment (and nothing else) in addition to the hit dice. Are there any additions to the list of choices that ought to be included, or animals that need to be shifted around to be worth it?

Or would this be better suited to the Homebrew section?

[sir_argenon]

i play that rangers get the companion @ lvl 4, as usual , but it starts as a lvl 4 companion, and, gets the full druid-progression from that point on.  it works just fine.

[X-Codes]

It greatly depends on the shtick you want it to accomplish.  The Druid Handbook does a cursory examination of all available animal companions.  If you want some kind of pseudo-Hood, then go with a good pouncer and have it pick up the relevant feats.  A level appropriate Crocodile is a nice hard-hitting grappler (although Freedom of Movement obsoletes that shtick really fast).  Some variety of Wolf can do a decent Combat Reflexes/Tripper routine, but it will need buffs to get the kind of reach a fighter has.  Bears are hard hitters, often with the requisite Dex to take Dodge-Mobility-Elusive Target, which actually makes them great tanks and flankers.

If your DM gives you enough leeway, you could template your AC with either the Magebred or Horrid templates, both in the ECS.  Horrid essentially bumps the animal up one category from the dire version (from -3 to -6), while Magebred apparently doesn't cause any adjustment whatsoever (see the Magebred Brown Bear and Magebred Ghost Tiger in Five Nations).  The latter, though, is extremely cheesy.