In Complete Champion, there are 3 variant builds. One requires you to give up spellcasting, one requires you to drop wild empathy, and the last one requires you to drop your animal companion. Bingo!
Spiritual Guide
Level 4th
You are befriended by a spiritual guide that aids you in the wilderness. Once you enter any civilized area larger than a hamlet, your spiritual guide departs, returning when you are back in the wild. The guide cannot fight or protect you, but it can give a sense of impending danger. It grants you a divine bonus of 1/4 ranger level on Handle Animal, Knowledge (nature), Listen, Search, Spot, and Survival checks. In addition, the spell Commune with Nature is added to your ranger spell list, and you are granted a free casting of it 1x/day.
So at 8th level, that's +2 to 6 skills -- the equivalent of a couple of feats, plus a free spell.
The other option is to really try to make the animal companion work. There are some ways to improve it. For example, At level 8, your ranger can get the enhanced 4th-level druid animal companions. If you selected the ape, you'd have an ally with 10' reach, so guarantee a lot of AOO. The 3 attacks per round would net you an extra 3d6 + 12 points of damage. That really helps to offset a ranger's waning potency as the levels go up.
Or you could get a dire bat. It can carry up to 173 pounds and fly 30' per round. If you can stay under that weight limit, you might have a new, awesome mount. His attacks are worse than the ape (just 1 bite at 1d8 + 4) but his AC is higher, so he won't get hit as much.
Then take Natural Bond feat from Complete Adventurer. It adds 3 to your "druid level" for determining the animal companions stats. A ranger's "druid level" is half his ranger level. So at level 8, he'd be equivalent of a 4th level druid. Yet with the feat, he'd be considered level 7. It almost offsets the "half ranger level" thing, which means more potency. Yay!
Finally, use the spell Nature's Favor (from Complete Adventurer, or Spell Compendium) to give your animal +1 to hit & damage for every 3 levels you have. It lasts 1 minute. If you have a 10 round battle and your ape companion hits 2 times per round, that's an extra 40 points of damage, so it's really not bad.
The Enrage Animal spell will also buff an animal companion. It grants +4 to Str & Con but AC becomes 2 worse. It's like the Nature's Favor spell, but with an AC penalty and bonus hit points. It's also just level 1 (Nature's Favor is level 2).
