Despite Acer facing lawsuits, they are continuing to do quite well in the notebook market. They continue to gain share over Dell and HP, and had very good success in 4Q 2006. Not only did they gain share, they also saw a significant increase in the total number of sales:

In the fourth quarter, Acer shipped about 3.4 million notebooks compared to the 2.3 million it shipped in the third quarter. HP, the world's leading PC vendor, saw its notebooks shipments increase by more than 32 percent in the same time period.
Though Acer is still considered a bit player in the notebook market, they are gaining fast – and the article brings out that if this trend continues, they very well could end up being the third “major” vendor for notebooks. The company has made it their intention to make it to the number 3 spot, and they are now there. They still do not have the numbers to impact HP and Dell, though clearly that won't last for long. The competition is tough, with Lenovo and Toshiba to contend with.

You can read a press release concerning their latest jumps in the comments section.