My laptop is starting to age and my battery life is not what it once was.

I first noticed the problem when SuSE would give my power warnings at 98%
After doing a little research I found out that I was trying to apply Nicad battery saving principles, which is a big no-no for LION type batteries.

I use my laptop as a desktop replacement, and I'm usually on it for long periods of time. What type of battery should I get, should I spring for a higher number of cells, what are some good brands or should I buy a battery straight from the manufacturer of the laptop (HP,) and how much money should I expect to spend on the new battery.

My laptop model is a HP dv1331se.

Any advice I can get would be very much appreciated.
Thanks.

I always like to purchase from the manufacturer. It might be higher priced, but I'm certain it will be the right battery for the laptop. If they make a higher cell battery and its within your budget, I'd say go for it.
I've never cared to look into the Lith-Ion vs the NiCad debate, so I'm no help there.

Thanks, I'll start looking around on HP's site for batteries.

Li-Ion is far superior to NiCad as the capacity doesn't reduce as quickly.