@DraconianTimes
I run FreeBSD (yes I know this is OpenBSD thread), on ThinkPad X300 and averything works smooth.
ThinkPad X301 has little newer Intel platform, so you must only check OpenBSD support for these:
GS45 chipset (with X4500 graphics), dunno if X301 has the same sound card as X300, but X300 has Azalia A1984A card which is supported by OpenBSD (dmesg part below).
azalia0: codecs: Analog Devices AD1984A, AT&T/Lucent/0x1040, using Analog Devices AD1984A
As for WiFi, newerX301 has 5100 Wireless.
Also check these threads:
http://www.mail-archive.com/misc@ope.../msg79540.html
If you want to be sure that it will work, get X300 with GS965 chipset (X3100 graphics) and 4965AGN Wireless.