Westthen,
Welcome to the club! I had originally planned to build one below RM1500 as well.

This is my setup for RM1700.

1. Silverstone SG-01B Evolution Casing <-- Budget Destroyer! (RM529)
2. Coolermaster 350W PSU (RM60 bundled deal with SG-01B)
3. Gigabyte MA78GM-S2H Motherboard (RM310)
4. Kingston 1Gb DDR2 RAM 800Mhz - X2 (RM160)
5. AMD 4850e cpu w/ stock HSF (RM288)
6. WD 500Gb SATA HD Greenpower (RM250)
7. Lite-On SATA DVD Writer (RM95)

I believe you can do it under RM1500 if you go for cheaper casings like Inwin or Icute. I haven't taken into account the cost for a wireless keyboard, but it is considered a luxury item if you're on a budget.

There are 2 main competing chipsets today (AMD 780G or the Nvidia 8200 chipset) that will work well for HTPC. Up to you read reviews and compare each motherboard manufacturer's offerings for each of these chipset to see which one suits you the best.

just bought this remote.. using postage. working great with vista ultimate.
http://forum.lowyat.net/index.php?showtopic=662901&hl=

p/s.. any recomendation of a good htpc casing? currently using xqbox but the space very cramped. planning to add second tv tuner and graphic card. xqbox casing suck.. even my frontpanel cannot fit because no space for cable routing.

My new HTPC cum file server. Specs are:

Intel C2D X6800
4GB DDR3-1333 HyperX
8600GT
Prodigy 7.1
Some 6TB of hdd space
Gigaworks T40
Dinovo Mini BT

I have a mini tower HTPC as well. I don't put it near the TV but at the far corner. Just need to have the remote censor in front of the TV that's all. No need to showcase the HTPC