Note, the following is pure speculation and should not be taken into consideration for purchasing decisions.
With the Mac mini, Apple is positioning itself to really get back into the mainstream PC market. One thing I think we'll see this year is the reworking of the pricing of their current line up. For one, when the iMacs get bumped up to 1.8 and 2.0 GHz, I wouldn't be surprised to see a $100 price drop across the line so they'd be starting at $1199 for a 1.8 GHz 17".
I think the biggest change will be to the PowerMac line. For the most part, they've been price out of most markets unless you compare them to high end gaming machines and Xeon work stations. I think the PowerMacs will we split into two lines, one singe processor and one dual processor, with the singles being aimed at the consumer market and they would be like the current sing 1.8 and have the bus speed of the iMacs. I wouldn't be surprised to see a singe processor(1.8 or 2.0 GHz depending on how speed bumps go) PowerMac G5 with 256MB of RAM(unless the finally make 512 the minimum), 80GB(possibly just 40GB, but that seems to low end for a PM) hard drive, 64MB video card and a combo drive go on sale for $999, although $1099 and $1199 are more plausible. The same would cost you $1399 right now, but I think comparing it too the imacs prices they are charging quite a premium and as supplies of parts increases, prices may come down.
Call me crazy, but I don't think it's too completely far fetched.