The wait wasn't for me and I got the White 13" 2.4GHz with 2GB of RAM. The difference between the two white MacBooks are
White 13"
2.1GHz
1GB of RAM
120GB HD
Next one is
White 13"
2.4GHz
2GB of RAM
160GB HD
They also have different disc drives which might affect what you are doing. The first one only has DVD-ROM and the next upgrade up gives you the ability to write DVDs which is the big difference in disc drives.
So you are paying an extra $300 ($999 for low and $1,200 for the upgrade) for a better disc drive, 1GB more of RAM, 40GB more on the HDD and .3GHz faster. I thought it was worth it and went for it. My laptop runs smoothly and amazing.
EDIT: Oops, didn't read the question. I don't think the update will be too big and not worth it. So I got mine now.