Compiling these modules, which are loaded on nearly every PC, in the kernel cuts down my boot time from 42s to 32s on my computer:
ata_generic ata_piix cdrom dm_mirror dm_mod dm_snapshot dm_zero ehci_hcd ext3 floppy i2c_core jbd libata mbcache ohci_hcd parport parport_pc pata_acpi scsi_mod sd_mod sg snd snd_mixer_oss snd_page_alloc snd_pcm snd_pcm_oss snd_seq snd_seq_device snd_seq_dummy snd_seq_midi_event snd_seq_oss snd_timer soundcore sr_mod uhci_hcd